commit: avoid allocation in clear_commit_marks_many()

Pass the entries of the commit array directly to clear_commit_marks_1()
instead of adding them to a commit_list first.  The function clears the
commit and any first parent without allocation; only higher numbered
parents are added to a list for later treatment.  This change extends
that optimization to clear_commit_marks_many().

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

commit.c

@@ -547,7 +547,7 @@ void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 	struct commit_list *list = NULL;
 
 	while (nr--) {
-		commit_list_insert(*commit, &list);
+		clear_commit_marks_1(&list, *commit, mark);
 		commit++;
 	}
 	while (list)