Add git/gerrit-on-borg utilities.

gob_util.py is a general-purpose library for communicating with the
gerrit-on-borg service.

testing_support/gerrit_test_case.py is a unittest framework for
testing code that interacts with gerrit.

R=vadimsh@chromium.org, cmp@chromium.org
BUG=

Review URL: https://codereview.chromium.org/26399002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@228965 0039d316-1c4b-4281-b951-d872f2087c98

testing_support/gerrit-init.sh

@@ -147,7 +147,7 @@ fi
 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}/