Test Architecture Tweak

As I was starting to write tests for sync-fork, wanted to try and simplify the test architecture a little bit.
Tests now update the remote with a second repository instead of using local and resetting.
This was just easier for me to think about and more closely mirrors reality.

@kevgo what do you think?

Note: I used git-extract to pull this off my sync-fork branch.
create_local_commits was doing a checkout of the branch if one was specified. 
I wanted to always specify it so I moved the checkout of the branch in there.