This fixes an issue introduced in afb0dce2

If no package name was given, fpm bailed out.
Added tests for commands without package -p <dir>
Merge pull request #691 from vStone/bugfix/File_directory_on_nil

This fixes an issue introduced by supporting -p <dir>
Fix post_install logging; protect previous current dir during clean up
Merge pull request #700 from gerbercj/feature/sh_package_bugfixes

Feature/sh package bugfixes
Use proper ruby versions on travis (rvm) + use bundler