title: Invalid byte sequence error in normalize_yaml_input being thrown?
body: <p>I'm getting the error (below) when trying to push my project to Heroku. Googling found a few people with similar issues turning up, but with a different gem as the last gem before the error, so I don't think it's got to do with warden. A few of the similar errors/github issues I found had solutions pointing back to a rubygems error, which was apparently <a href="https://github.com/rubygems/rubygems/issues/139#issuecomment-1894945">to be fixed in 1.8.10</a> (which I've got already, so I'm doubtful that it's that issue either.</p>
  
  <p>Any suggestions would be appreciated—I'm sure it's something simple I've missed.</p>
  
  <pre><code>cobychapple at shiva in ~/code/zzz on master!
  ± git push heroku master
  Counting objects: 201, done.
  Delta compression using up to 2 threads.
  Compressing objects: 100% (181/181), done.
  Writing objects: 100% (201/201), 92.14 KiB, done.
  Total 201 (delta 38), reused 0 (delta 0)
  
  -----&gt; Heroku receiving push
  -----&gt; Ruby/Rails app detected
  -----&gt; Detected Rails is not set to serve static_assets
         Installing rails3_serve_static_assets... done
  -----&gt; Configure Rails 3 to disable x-sendfile
         Installing rails3_disable_x_sendfile... done
  -----&gt; Configure Rails to log to stdout
         Installing rails_log_stdout... done
  -----&gt; Gemfile detected, running Bundler version 1.0.7
         Unresolved dependencies detected; Installing...
         Using --without development:test
         Fetching source index for http://rubygems.org/
         Installing rake (0.9.2.2) 
         Installing multi_json (1.0.3) 
         Installing activesupport (3.1.2) 
         Installing builder (3.0.0) 
         Installing i18n (0.6.0) 
         Installing activemodel (3.1.2) 
         Installing erubis (2.7.0) 
         Installing rack (1.3.5) 
         Installing rack-cache (1.1) 
         Installing rack-mount (0.8.3) 
         Installing rack-test (0.6.1) 
         Installing hike (1.2.1) 
         Installing tilt (1.3.3) 
         Installing sprockets (2.1.2) 
         Installing actionpack (3.1.2) 
         Installing mime-types (1.17.2) 
         Installing polyglot (0.3.3) 
         Installing treetop (1.4.10) 
         Installing mail (2.3.0) 
         Installing actionmailer (3.1.2) 
         Installing arel (2.2.1) 
         Installing tzinfo (0.3.31) 
         Installing activerecord (3.1.2) 
         Installing activeresource (3.1.2) 
         Installing addressable (2.2.6) 
         Installing bcrypt-ruby (3.0.1) with native extensions 
         Installing coffee-script-source (1.1.3) 
         Installing execjs (1.2.9) 
         Installing coffee-script (2.2.0) 
         Installing rack-ssl (1.3.2) 
         Installing json (1.6.1) with native extensions 
         Installing rdoc (3.11) 
         Installing thor (0.14.6) 
         Installing railties (3.1.2) 
         Installing coffee-rails (3.1.1) 
         Installing orm_adapter (0.0.5) 
         Installing warden (1.1.0) 
         /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/specification.rb:519:in `normalize_yaml_input': invalid byte sequence in US-ASCII (ArgumentError)
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/specification.rb:479:in `from_yaml'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/package/tar_input.rb:183:in `load_gemspec'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/package/tar_input.rb:51:in `block in initialize'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/package/tar_reader.rb:64:in `block in each'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/package/tar_reader.rb:55:in `loop'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/package/tar_reader.rb:55:in `each'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/package/tar_input.rb:32:in `initialize'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/package/tar_input.rb:17:in `new'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/package/tar_input.rb:17:in `open'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/package.rb:58:in `open'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/format.rb:63:in `from_io'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/format.rb:51:in `block in from_file_by_path'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/open-uri.rb:35:in `open'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/open-uri.rb:35:in `open'
          from /usr/ruby1.9.2/lib/ruby/1.9.1/rubygems/format.rb:50:in `from_file_by_path'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/source.rb:72:in `fetch'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/installer.rb:45:in `block in run'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/spec_set.rb:12:in `block in each'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/spec_set.rb:12:in `each'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/spec_set.rb:12:in `each'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/installer.rb:44:in `run'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/installer.rb:8:in `install'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/cli.rb:225:in `install'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/vendor/thor/task.rb:22:in `run'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/vendor/thor/invocation.rb:118:in `invoke_task'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/vendor/thor.rb:246:in `dispatch'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/lib/bundler/vendor/thor/base.rb:389:in `start'
          from /usr/ruby1.9.2/lib/ruby/gems/1.9.1/gems/bundler-1.0.7/bin/bundle:13:in `&lt;top (required)&gt;'
          from /usr/ruby1.9.2/bin/bundle:19:in `load'
          from /usr/ruby1.9.2/bin/bundle:19:in `&lt;main&gt;'
         FAILED: http://devcenter.heroku.com/articles/bundler
   !     Heroku push rejected, failed to install gems via Bundler
  
  To git@heroku.com:zzz.git
   ! [remote rejected] master -&gt; master (pre-receive hook declined)
  error: failed to push some refs to 'git@heroku.com:zzz.git'
  </code></pre>
  
  <p>Here's the output of <code>bundle install</code> too, in case it helps:</p>
  
  <pre><code>cobychapple at shiva in ~/code/zzz on master
  ± bundle install
  Using rake (0.9.2.2) 
  Using multi_json (1.0.3) 
  Using activesupport (3.1.2) 
  Using builder (3.0.0) 
  Using i18n (0.6.0) 
  Using activemodel (3.1.2) 
  Using erubis (2.7.0) 
  Using rack (1.3.5) 
  Using rack-cache (1.1) 
  Using rack-mount (0.8.3) 
  Using rack-test (0.6.1) 
  Using hike (1.2.1) 
  Using tilt (1.3.3) 
  Using sprockets (2.1.2) 
  Using actionpack (3.1.2) 
  Using mime-types (1.17.2) 
  Using polyglot (0.3.3) 
  Using treetop (1.4.10) 
  Using mail (2.3.0) 
  Using actionmailer (3.1.2) 
  Using arel (2.2.1) 
  Using tzinfo (0.3.31) 
  Using activerecord (3.1.2) 
  Using activeresource (3.1.2) 
  Using addressable (2.2.6) 
  Using ansi (1.4.1) 
  Using bcrypt-ruby (3.0.1) 
  Using bundler (1.0.18) 
  Using coffee-script-source (1.1.3) 
  Using execjs (1.2.9) 
  Using coffee-script (2.2.0) 
  Using rack-ssl (1.3.2) 
  Using json (1.6.1) 
  Using rdoc (3.11) 
  Using thor (0.14.6) 
  Using railties (3.1.2) 
  Using coffee-rails (3.1.1) 
  Using orm_adapter (0.0.5) 
  Using warden (1.1.0) 
  Using devise (1.5.1) 
  Using faker (1.0.1) 
  Using rails (3.1.2) 
  Using formtastic (2.0.2) 
  Using formtastic-bootstrap (1.0.1) 
  Using haml (3.1.3) 
  Using launchy (2.0.5) 
  Using rest-client (1.6.7) 
  Using rubyzip (0.9.4) 
  Using term-ansicolor (1.0.7) 
  Using heroku (2.14.0) 
  Using jquery-rails (1.0.18) 
  Using kaminari (0.12.4) 
  Using populator (1.0.0) 
  Using sass (3.1.10) 
  Using sass-rails (3.1.5) 
  Using sequel (3.20.0) 
  Using sinatra (1.0) 
  Using sqlite3 (1.3.4) 
  Using sqlite3-ruby (1.3.3) 
  Using taps (0.3.23) 
  Using turn (0.8.2) 
  Using uglifier (1.1.0) 
  Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed.
  </code></pre>
  
  <p>Rubygems version:</p>
  
  <pre><code>cobychapple at shiva in ~/code/zzz on master
  ± gem -v
  1.8.10
  </code></pre>