Remove jruby-specific fix in rbenv hook for finding standard gem install path (this was actually fixed by the earlier recursion fix, and should have been removed then). Thanks to @neovatar for starting me down this path (https://github.com/neovatar/rbenv-gemset/commit/ef779f42416373ad98b7a527b06b3ada5e48bf7e)!

Also bump version to 0.5.*6*! (0.5.5 should have been the last commit)