Revert "Decouple the removal of GEM_HOME and GEM_ROOT (just in case)."
Revert "Decouple the removal of GEM_HOME and GEM_ROOT (just in case)."

* Why do I keep wanting to do this. The logic of chruby dictates that
  GEM_HOME and GEM_ROOT are to be coupled.

ngpestelos/chruby,postmodern/chruby,kbrock/chruby,postmodern/chruby,kbrock/chruby,eunomie/chgo,JeanMertz/chruby-fish,eunomie/chgo,ilikepi/chruby,rstacruz/chruby-fish,regularfry/chruby,rstacruz/chruby-fish,JeanMertz/chruby-fish,ngpestelos/chruby,ilikepi/chruby,regularfry/chruby