Revert "Added tests for removing additional leading/trailing colons."
Revert "Added tests for removing additional leading/trailing colons."

* We only want to remove the first and last : from PATH, which we added.

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