Be verbose when !initial commit

verbose option in git-commit.sh lead us to run git-diff-index, which
needs a commit-ish we are making diff against.  When we are commiting
the fist set, we obviously don't have any commit-ish in the repo.  So
we just skip the git-diff-index run.

It might be possible to produce diff against empty but do we need
that?

Signed-off-by: Yasushi SHOJI <yashi@atmark-techno.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-commit.sh

@@ -161,7 +161,7 @@ run_status () {
 	    }
 	'
 
-	if test -n "$verbose"
+	if test -n "$verbose" -a -z "$IS_INITIAL"
 	then
 	    git-diff-index --cached -M -p --diff-filter=MDTCRA $REFERENCE
 	fi