builtin-commit.c: add -u as short name for --untracked-files

This makes the C code consistent with the documentation and the old shell
code.

Signed-off-by: Sitaram Chamarty <sitaramc@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-commit.c

@@ -100,7 +100,7 @@ static struct option builtin_commit_options[] = {
 	OPT_BOOLEAN('o', "only", &only, "commit only specified files"),
 	OPT_BOOLEAN('n', "no-verify", &no_verify, "bypass pre-commit hook"),
 	OPT_BOOLEAN(0, "amend", &amend, "amend previous commit"),
-	OPT_BOOLEAN(0, "untracked-files", &untracked_files, "show all untracked files"),
+	OPT_BOOLEAN('u', "untracked-files", &untracked_files, "show all untracked files"),
 	OPT_BOOLEAN(0, "allow-empty", &allow_empty, "ok to record an empty change"),
 	OPT_STRING(0, "cleanup", &cleanup_arg, "default", "how to strip spaces and #comments from message"),