Fix mitaka-dvr-ceph docker repo

- Add repository for docker-ce package instead of docker.io
- Adding to https://review.gerrithub.io/c/Mirantis/tcp-qa/+/434035/

Change-Id: I8bd19f683e1c1f379048095caa7db4f2c1bd6cdc
diff --git a/tcp_tests/templates/cookied-mcp-mitaka-dvr-ceph/_context-environment.yaml b/tcp_tests/templates/cookied-mcp-mitaka-dvr-ceph/_context-environment.yaml
index 89bf918..cb7f4cb 100644
--- a/tcp_tests/templates/cookied-mcp-mitaka-dvr-ceph/_context-environment.yaml
+++ b/tcp_tests/templates/cookied-mcp-mitaka-dvr-ceph/_context-environment.yaml
@@ -137,6 +137,8 @@
       roles:
       - openstack_gateway
       - linux_system_codename_xenial
+      classes:
+      - system.linux.system.repo.mcp.apt_mirantis.docker
       interfaces:
         ens3:
           role: single_dhcp