core: Actually return an error from fsck

And add some tests that fsck reports an error.

tests/t0005-corruption.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+#
+# Copyright (C) 2011 Colin Walters <walters@verbum.org>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+#
+# Author: Colin Walters <walters@verbum.org>
+
+set -e
+
+echo "1..1"
+
+. libtest.sh
+
+setup_test_repository "regular"
+$OSTREE checkout test2 checkout-test2
+cd checkout-test2
+chmod o+x firstfile
+$OSTREE fsck -q 2>/dev/null && (echo 1>&2 "fsck unexpectedly succeeded"; exit 1)
+chmod o-x firstfile
+$OSTREE fsck -q
+
+echo "ok chmod"