Configure HOME for the gerrit process.

This prevents jgit from parsing the user's existing ~/.gitconfig,
which can skew test results.

BUG=

Review URL: https://codereview.chromium.org/27752003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@229245 0039d316-1c4b-4281-b951-d872f2087c98

testing_support/gerrit-init.sh

@@ -157,6 +157,8 @@ cat <<EOF > "${rundir}/etc/gerrit.config"
 	listenAddress = *:${ssh_port}
 [sendemail]
 	enable = false
+[container]
+	javaOptions = -Duser.home=${rundir}/tmp
 EOF
 
 # Initialize the gerrit instance.