Removed .ruby-gemset file.

From now on we won't use gemsets, they complicate things unnecessarily and don't really add anything in projects that use Bundler.
Changed ruby version to 1.9.3-p448 in the capistrano deployment. Also no gemset is used, RVM is told to use the default gemset.

Gemsets were a lot of trouble sometimes and they didn't really add anything worth it. Default gemset from now on it is.