Add missing docker_registry_insecure in globals.yml

Change-Id: I99d4ea6ca615bdde83cd55d91672733d9b95372a
Signed-off-by: Radosław Piliszek <radoslaw.piliszek@gmail.com>

etc/kolla/globals.yml

@@ -54,6 +54,7 @@
 
 #docker_registry: "172.16.0.10:4000"
 #docker_namespace: "companyname"
+#docker_registry_insecure: "yes"
 #docker_registry_username: "sam"
 #docker_registry_password: "correcthorsebatterystaple"