resolve #228: git sync abort edge case

@kevgo
Not really. Thats why this bug was never really caught before. 

* git sync: 
  * This only happens when you abort after merging the main branch and there were remote branch updates (what I added tests for)
* git ship
  * Same as git-sync (did not add tests for this)
  * When entering an empty commit message, it resets any changes to the branch you are shipping (thus needed to change the single git ship test I did)