get branch of commit on detached head

I've been using gitversion with tfs build and had some issues with building the master branch which I think is related to issue ParticularLabs/GitVersion#179 although other branches build correctly.

When the repository is checked out the HEAD points to master. The commit is then checked out to a detached branch. On the develop/feature/release branches the sha commit will be different so GitVersion correctly gets the branch.

If you are building the master branch then 2 branches are found as the HEAD is pointing to the master with the same commit. As we are building a remote branch we should only look for the commit in the tracking branches.

Thanks
Gruff