pull: Add depth support

For mirroring in particular, we really want to be able to traverse
all history.

$ ostree --repo=repo pull --mirror --depth=-1

https://bugzilla.gnome.org/show_bug.cgi?id=739240

tests/test-pull-depth.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+#
+# Copyright (C) 2014 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
+
+setup_fake_remote_repo1 "archive-z2"
+
+echo '1..1'
+
+cd ${test_tmpdir}
+mkdir repo
+${CMD_PREFIX} ostree --repo=repo init
+${CMD_PREFIX} ostree --repo=repo remote add --set=gpg-verify=false origin $(cat httpd-address)/ostree/gnomerepo
+
+ostree --repo=repo pull --depth=0 origin main
+find repo/objects -name '*.commit' | wc -l > commitcount
+assert_file_has_content commitcount "^1$"
+
+ostree --repo=repo pull --depth=0 origin main
+find repo/objects -name '*.commit' | wc -l > commitcount
+assert_file_has_content commitcount "^1$"
+
+ostree --repo=repo pull --depth=1 origin main
+find repo/objects -name '*.commit' | wc -l > commitcount
+assert_file_has_content commitcount "^2$"
+
+ostree --repo=repo pull --depth=1 origin main
+find repo/objects -name '*.commit' | wc -l > commitcount
+assert_file_has_content commitcount "^2$"
+
+ostree --repo=repo pull --depth=-1 origin main
+find repo/objects -name '*.commit' | wc -l > commitcount
+assert_file_has_content commitcount "^3$"
+
+echo "ok pull depth"