[ci] Enable heat for magnum job

Change-Id: I075371ba5b1c501eae8cdd9ca6a6124c09e17ea2

.zuul.d/rally-task-magnum.yaml

@@ -8,10 +8,12 @@
       - name: openstack/rally-openstack
       - name: openstack/magnum
       - name: openstack/python-magnumclient
+      - name: openstack/heat
     vars:
       devstack_plugins:
         rally-openstack: https://git.openstack.org/openstack/rally-openstack
         magnum: https://git.openstack.org/openstack/magnum
+        heat: https://git.openstack.org/openstack/heat
       devstack_services:
         magnum: true
         # disable redundant services for the job

rally-jobs/magnum.yaml

@@ -1,7 +1,7 @@
 {% set image = "Fedora-Atomic-27-20180212.2.x86_64" %}
 ---
   version: 2
-  title: Task for gate-rally-dsvm-magnum-rally-nv job
+  title: Task for rally-task-magnum job
   description: >
     This task contains various subtasks for testing magnum plugins
   subtasks: