Changed ChefDK::Helpers.omnibus_env to set GEM_HOME to Gem.user_dir instead of GEM_HOME. Also changed the tests to expect that as well. It works for me, but really not clear where Gem.user_dir comes from and if this may cause other people other problems.
Merge pull request #160 from rberger/rjb-gem_home

Set GEM_HOME to Gem.user_dir instead of Gem.paths.home