"rhpkg patch" behavior on different commits with same commit title

[tserlin]

I noticed this today when someone cherry-picked a new commit to our -patches branch: the new commit had the same title as an older commit (but contained different code), and "rhpkg patch" correctly added the patch, but placed "Updated patches" in the commit message.

Not a big deal in that it's easy to work around, but I think the main thing is that it leaves no audit trail for the affected BZ in our dist-git branch.