Strips the refs/heads/ if any to get just the branchName out of a :ref
e.g.: `refs/heads/feature/newProfile` -> `feature/newProfile`

The TeamCity buildQueue POST data require the branchName attribute
to contain just the branch name (just xyzbranch and not the full
ref in the refs/heads/xyzbranch). With the refs/heads/xyzbranch the
build is triggered and looks like it is working however it always
ompiles the default branch (or master).