[lfmerge] Update version number calculation
[lfmerge] Update version number calculation

This change restores the `Major.Minor.Patch.BuildNumber` version
number that we had previously. With a newer GitVersion the branch
name sneaked in.

Change-Id: Ia292efde8122180085aa312f65b01367bd7fa372

sillsdev/ci-builder-scripts,sillsdev/ci-builder-scripts,sillsdev/ci-builder-scripts