reflog-delete: parse standard reflog options

Add support for some standard reflog options such as --dry-run and
--verbose to the reflog delete subcommand.
Signed-off-by: NBrandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

builtin-reflog.c

@@ -14,6 +14,8 @@
 
 static const char reflog_expire_usage[] =
 "git-reflog (show|expire) [--verbose] [--dry-run] [--stale-fix] [--expire=<time>] [--expire-unreachable=<time>] [--all] <refs>...";
+static const char reflog_delete_usage[] =
+"git-reflog delete [--verbose] [--dry-run] <refs>...";
 
 static unsigned long default_reflog_expire;
 static unsigned long default_reflog_expire_unreachable;
@@ -425,12 +427,28 @@ static int cmd_reflog_delete(int argc, const char **argv, const char *prefix)
 	struct cmd_reflog_expire_cb cb;
 	int i, status = 0;
 
-	if (argc < 2)
-		return error("Nothing to delete?");
-
 	memset(&cb, 0, sizeof(cb));
 
 	for (i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+		if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
+			cb.dry_run = 1;
+		else if (!strcmp(arg, "--verbose"))
+			cb.verbose = 1;
+		else if (!strcmp(arg, "--")) {
+			i++;
+			break;
+		}
+		else if (arg[0] == '-')
+			usage(reflog_delete_usage);
+		else
+			break;
+	}
+
+	if (argc - i < 1)
+		return error("Nothing to delete?");
+
+	for ( ; i < argc; i++) {
 		const char *spec = strstr(argv[i], "@{");
 		unsigned char sha1[20];
 		char *ep, *ref;