title: iconv deprecation warning with ruby 1.9.3
body: <p>I'm getting this warning when I run rspec: </p>
  
  <pre>
  /gems/activesupport-3.1.0/lib/active_support/dependencies.rb:240:in `block in require': iconv will be deprecated in the future, use String#encode instead.
  </pre>
  
  <p>I get the same warning with rails <code>3.1.0</code>, <code>3.1.1</code>, <code>3.1.2.rc2</code> versions. Seems it's related to <code>sqlite3</code> gem, but I'm not sure. There are no warnings with ruby 1.9.2       </p>
  
  <p>Any suggestions how to deal with it?</p>