Add git/gerrit-on-borg utilities.

testing_support/gerrit-init.sh

 #!/bin/bash
 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 set -e
 
 http_port=8080
 ssh_port=29418
 
@@ skipping 129 matching lines @@
   echo "       to download the latest version." 1>&2
   exit 1
 fi
 
 # By default, gerrit only accepts https connections, which is a good thing.  But
 # for testing, it's convenient to enable plain http.  Also, turn off all email
 # notifications.
 mkdir -p "${rundir}/etc"
 cat <<EOF > "${rundir}/etc/gerrit.config"
 [auth]
-        type = http
+        type = DEVELOPMENT_BECOME_ANY_ACCOUNT
         gitBasicAuth = true
 [gerrit]
         canonicalWebUrl = http://$(hostname):${http_port}/
 [httpd]
         listenUrl = http://*:${http_port}/
 [sshd]
         listenAddress = *:${ssh_port}
 [sendemail]
         enable = false
 EOF
@@ skipping 37 matching lines @@
 To use SSH API:
   ssh ${username}@localhost -p ${ssh_port} -i ${rundir}/tmp/id_rsa gerrit
 
 To enable 'git push' without a password prompt:
   git config credential.helper 'store --file=${rundir}/tmp/.git-credentials'
 
 To stop the server:
   ${rundir}/bin/gerrit.sh stop
 
 EOF