builtin-fetch.c (store_updated_refs): Honor update_local_ref() return value

Sync with builtin-fetch--tool.c where append_fetch_head()
honors update_local_ref() return value.

This fixes non fast forward fetch exit status,
http://bugzilla.altlinux.org/show_bug.cgi?id=15037

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5518-fetch-exit-status.sh

@@ -0,0 +1,37 @@
+#!/bin/sh
+#
+# Copyright (c) 2008 Dmitry V. Levin
+#
+
+test_description='fetch exit status test'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+
+	>file &&
+	git add file &&
+	git commit -m initial &&
+
+	git checkout -b side &&
+	echo side >file &&
+	git commit -a -m side &&
+
+	git checkout master &&
+	echo next >file &&
+	git commit -a -m next
+'
+
+test_expect_success 'non fast forward fetch' '
+
+	test_must_fail git fetch . master:side
+
+'
+
+test_expect_success 'forced update' '
+
+	git fetch . +master:side
+
+'
+
+test_done