format-patch: give --reroll-count a short synonym -v

Accept "-v" as a synonym to "--reroll-count", so that users can say
"git format-patch -v4 master", instead of having to fully spell it
out as "git format-patch --reroll-count=4 master".

As I do not think of a reason why users would want to tell the
command to be "verbose", I think this should be OK.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-format-patch.txt

@@ -18,7 +18,7 @@ SYNOPSIS
 		   [--start-number <n>] [--numbered-files]
 		   [--in-reply-to=Message-Id] [--suffix=.<sfx>]
 		   [--ignore-if-in-upstream]
-		   [--subject-prefix=Subject-Prefix] [--reroll-count <n>]
+		   [--subject-prefix=Subject-Prefix] [(--reroll-count|-v) <n>]
 		   [--to=<email>] [--cc=<email>]
 		   [--cover-letter] [--quiet]
 		   [<common diff options>]
@@ -166,6 +166,7 @@ will want to ensure that threading is disabled for `git send-email`.
 	allows for useful naming of a patch series, and can be
 	combined with the `--numbered` option.
 
+-v <n>::
 --reroll-count=<n>::
 	Mark the series as the <n>-th iteration of the topic. The
 	output filenames have `v<n>` pretended to them, and the

builtin/log.c

@@ -1081,7 +1081,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 			    N_("use <sfx> instead of '.patch'")),
 		OPT_INTEGER(0, "start-number", &start_number,
 			    N_("start numbering patches at <n> instead of 1")),
-		OPT_INTEGER(0, "reroll-count", &reroll_count,
+		OPT_INTEGER('v', "reroll-count", &reroll_count,
 			    N_("mark the series as Nth re-roll")),
 		{ OPTION_CALLBACK, 0, "subject-prefix", &rev, N_("prefix"),
 			    N_("Use [<prefix>] instead of [PATCH]"),

t/t4014-format-patch.sh

@@ -245,6 +245,14 @@ test_expect_success 'reroll count' '
 	! grep -v "^Subject: \[PATCH v4 [0-3]/3\] " subjects
 '
 
+test_expect_success 'reroll count (-v)' '
+	rm -fr patches &&
+	git format-patch -o patches --cover-letter -v4 master..side >list &&
+	! grep -v "^patches/v4-000[0-3]-" list &&
+	sed -n -e "/^Subject: /p" $(cat list) >subjects &&
+	! grep -v "^Subject: \[PATCH v4 [0-3]/3\] " subjects
+'
+
 check_threading () {
 	expect="$1" &&
 	shift &&