[BZ#698633] can't run 'git commit' with no filename

Submitted by Adam Dingle

Description

Currently if I right click the root of a local repository and select Commit, Meld runs 'git commit .' Usually that works to commit all outstanding changes, but when a cherry-pick is in progress it fails:

fatal: cannot do a partial commit during a cherry-pick. Exit code: 128

In this situation only a 'git commit' with no filename will work. I think Meld should run a simple 'git commit' if the user commits when the top-level directory is selected or if nothing is selected at all.

This is similar to bug 698564, by the way.