title: Bundle install tries to use cache file
body: <p>When i try to do bundle install, my gem_path and gem_home point to /usr/local/rvm/gems/ which i don't have write access and it fails because of invalid permissions. because of this i've changed both paths to a local directory where i do have write access.</p>
  
  <p>when doing so, i do  a bundle install, i get :</p>
  
  <pre><code>bruno@test6:~$ bundle install
  Fetching gem metadata from https://rubygems.org/.........
  Fetching gem metadata from https://rubygems.org/..
  
  Bundler::GemspecError: Could not read gem at   /afs/varda.io/user/b/br/bruno/test6/cache/rake-10.1.0.gem. It may be corrupted.
  An error occurred while installing rake (10.1.0), and Bundler cannot continue.
  Make sure that `gem install rake -v '10.1.0'` succeeds before bundling.
  </code></pre>
  
  <p>well, if i do a gem install, it works just fine.</p>
  
  <p>but bundle would just not work; even if a try to delete the cache folder that it complains about.</p>
  
  <p>i did try "bundle install --no-cache" and it fails in the same way. (bundle install --deployment works fine too) how do i get bundle install to work ?</p>
  
  <p>i've spent quite a bit of time, if anyone would have any guidance , i would really appreciate it!</p>