Add manila-service-security-group to limit manila ports (#412)

manila-service-security-group to service project that will later create
manila share instances on
diff --git a/roles/manila/vars/main.yml b/roles/manila/vars/main.yml
index abde25e..c6e2cfa 100644
--- a/roles/manila/vars/main.yml
+++ b/roles/manila/vars/main.yml
@@ -53,6 +53,7 @@
         path_to_public_key: /etc/manila/ssh-keys/id_rsa.pub
         service_image_name: "{{ manila_image_name }}"
         service_instance_flavor_id: "{{ _manila_flavor.id }}"
+        service_instance_security_group: "{{ _manila_service_security_group.id }}"
       keystone_authtoken:
         # NOTE(okozachenko1203): We can remove it once the following is merged:
         #                        https://review.opendev.org/883066