project: Don't emit locally modified hook warning in quiet mode

Change-Id: I0f6db037b85f2a015fc7b7fd37472df848a58266
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/254698
Reviewed-by: Mike Frysinger <vapier@google.com>
Tested-by: David Pursehouse <dpursehouse@collab.net>