show-branch: Fix die message in parse_reflog_param()

Commit 76a44c5 (show-branch --reflog: show the reflog message at the
top, 2007-01-19) introduced parse_reflog_param(). The die() call was
incorrectly passed arg + 9, when it should have been passed arg.

Signed-off-by: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-show-branch.c

@@ -576,7 +576,7 @@ static void parse_reflog_param(const char *arg, int *cnt, const char **base)
 	if (*ep == ',')
 		*base = ep + 1;
 	else if (*ep)
-		die("unrecognized reflog param '%s'", arg + 9);
+		die("unrecognized reflog param '%s'", arg);
 	else
 		*base = NULL;
 	if (*cnt <= 0)