Enable loading gerrit in iframe

Change-Id: Ib5bf4cbd7f221788318495ea51d7b4574c78c50c
diff --git a/docker/swarm/service/gerrit.yml b/docker/swarm/service/gerrit.yml
index c26c896..10e0629 100644
--- a/docker/swarm/service/gerrit.yml
+++ b/docker/swarm/service/gerrit.yml
@@ -29,6 +29,7 @@
             GERRIT_ADMIN_SSH_PUBLIC: ${_param:gerrit_admin_public_key}
             GERRIT_ADMIN_PWD: ${_param:gerrit_admin_password}
             GERRIT_ADMIN_EMAIL: ${_param:gerrit_admin_email}
+            CANLOADINIFRAME: "true"
           restart:
             condition: any
           image: ${_param:docker_image_gerrit}