TDD: add testcase for setting language with env var
Set language from environment variable, remove command line option to do so
Remove test for command line option
Use if instead of unless
modifier 'if' for rubocop
Merge pull request #138 from SUSE/review_140714_specify_language_with_envvar

[Review] Request from 'wstephenson' @ 'SUSE/connect/review_140714_specify_language_with_envvar'