Update the Tempest plugin to point towards the new plugin

The Magnum service has split it's tests for Tempest in a seperate
repo so this patch updates it.

This patch removes the linting issue for systemd daemon-reload
because the feature does not exist in the older Ansible release
used in stable/pike.

Co-Authored-By: Jean-Philippe Evrard <jean-philippe@evrard.me>
Closes-Bug: #1747607
Depends-On: I5f1ecb71c6125c29d6487bef6c2be215c1b561c1
Change-Id: Ia4e323eda453ae3e8dacf3dcf14d175e00727b4f
(cherry picked from commit d484d3097e)

tests/os_magnum-overrides.yml

@@ -3,11 +3,11 @@ tempest_run: yes
 
 tempest_plugins:
   - name: magnum
-    repo: https://git.openstack.org/openstack/magnum
+    repo: https://git.openstack.org/openstack/magnum-tempest-plugin
     branch: master
 
 tempest_test_whitelist:
-  - magnum.tests.functional.api.v1.test_cluster.ClusterTest.test_create_cluster*
+  - magnum_tempest_plugin.tests.api.v1.test_cluster.ClusterTest.test_create_cluster*
 
 tempest_flavors:
   - name: m1.magnum