magit/magit — pull request #933 by praet (2013-09-24 06:22:53+00:00)
Title: fix last `magit-git-string' victim

Fixing another victim of the semantic change in `magit-git-string` (commit f8d304a1).

@tarsius:
I've checked all functions which make use of `magit-git-string`.
This should be the only one left to fix.