In the past we've ran into errors where RBTools commands weren't properly

trying to find the right repository to use, and weren't outputting a nice

error message when it failed to find repositories. We had a fix for this,

but we missed one are where we also needed to apply the fix. This change adds

the fix for that area, and makes sure we've fixed this everywhere.

Ran rbt login in a random directory with no configured repository, saw

  a proper error message.
Ran unit tests.
Audited the rest of the code for this problem.