sysroot: Cleanup refs and prune even on last undeployment

I was working on a different test, and ended up being very confused at
the behavior where removing the last deployment didn't remove the last
`ostree/X/X/X` ref pointing to its commit.

There's no reason to special case the last undeployment AFAIK, and the
existing code handles this.

tests/test-admin-deploy-clean.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+#
+# Copyright (C) 2015 Colin Walters <walters@verbum.org>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the
+# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+
+set -e
+
+. $(dirname $0)/libtest.sh
+
+# Exports OSTREE_SYSROOT so --sysroot not needed.
+setup_os_repository "archive-z2" "syslinux"
+
+echo "1..1"
+
+ostree --repo=sysroot/ostree/repo pull-local --remote=testos testos-repo testos/buildmaster/x86_64-runtime
+rev=$(${CMD_PREFIX} ostree --repo=sysroot/ostree/repo rev-parse testos/buildmaster/x86_64-runtime)
+export rev
+ostree admin deploy --karg=root=LABEL=MOO --karg=quiet --os=testos testos:testos/buildmaster/x86_64-runtime
+ostree admin undeploy 0
+ostree --repo=sysroot/ostree/repo refs > refs.txt
+assert_not_file_has_content refs.txt '^ostree/'
+
+echo "ok deploy + undeploy repo prune"