cleanup: move tests to use ensure-package-repositories

In order to keep things clean, let's re-use the role we have
for setting up repos.

Change-Id: I989c4d45e28f94767ff9d63937d273d0542312f5

test-playbooks/registry/buildset-registry-pre.yaml

@@ -1,9 +1,10 @@
 - hosts: all
+  roles:
+    - name: ensure-package-repositories
+      repositories_list:
+        - repo: ppa:projectatomic/ppa
+
   tasks:
-    - name: Add project atomic PPA
-      become: true
-      apt_repository:
-        repo: ppa:projectatomic/ppa
     - name: Install packages
       become: true
       package:

test-playbooks/registry/test-registry-pre.yaml

@@ -34,11 +34,11 @@
 
 - hosts: executor
   name: Set up a simulated executor
+  roles:
+    - name: ensure-package-repositories
+      repositories_list:
+        - repo: ppa:projectatomic/ppa
   tasks:
-    - name: Add project atomic PPA
-      become: true
-      apt_repository:
-        repo: ppa:projectatomic/ppa
     - name: Install packages
       become: true
       package: