Bumped ruby version to newest 1.9.3

Otherwise this message is always displayed when entering the folder
ruby-1.9.3-p484 is not installed.
To install do: 'rvm install ruby-1.9.3-p484'

And running up to date software is never a failure (even when
1.9.3 is no longer maintained)
Land #3281, require latest Ruby 1.9.3

Note, this will cause developer environments to complain until Ruby is
reinstalled. It's probably a good idea to reinstall anyway, though,
since people who haven't in a while may have been linked against a
Heartbleed-vulnerable openssl library.