Docker: Make gerrit user own site's logs structure

Before this change, the starting gerrit was unable to write log files
under that directory. Should this issue become visible for the
stable-2.14 version of this plugin, then this commit may be
cherry-picked to fix that if necessary.

With this change, the whole site directory structure should be owned by
the gerrit user.

Change-Id: I25215487487b979053bef0a19e4a293d474177f6

src/test/docker/gerrit/start.sh

diff --git a/src/test/docker/gerrit/start.sh b/src/test/docker/gerrit/start.sh
index 8666485..f3d4560 100755
--- a/src/test/docker/gerrit/start.sh
+++ b/src/test/docker/gerrit/start.sh
@@ -22,7 +22,7 @@
 sudo -u gerrit java -jar /var/gerrit/bin/gerrit.war reindex -d /var/gerrit
 sudo -u gerrit git config -f /var/gerrit/etc/gerrit.config gerrit.canonicalWebUrl http://$HOSTNAME/
 
-touch /var/gerrit/logs/{gc_log,error_log,httpd_log,sshd_log,replication_log} && tail -f /var/gerrit/logs/* | grep --line-buffered -v 'HEAD /' &
+sudo -u gerrit touch /var/gerrit/logs/{gc_log,error_log,httpd_log,sshd_log,replication_log} && tail -f /var/gerrit/logs/* | grep --line-buffered -v 'HEAD /' &
 
 echo "Running Gerrit ..."
 sudo -u gerrit /etc/init.d/gerrit run