ci/papr: Update to f27-primary

I didn't try porting some of the other contexts yet...I want to see
if this works.

Note that FAHC was switched to 27, so it's only luck that things
work on 26.

Closes: #1108
Approved by: jlebon

.papr.yml

@@ -3,20 +3,20 @@ branches:
     - auto
     - try
 
-context: f26-primary
+context: f27-primary
 
 required: true
 
 cluster:
   hosts:
     - name: vmcheck1
-      distro: fedora/26/atomic
+      distro: fedora/27/atomic
     - name: vmcheck2
-      distro: fedora/26/atomic
+      distro: fedora/27/atomic
     - name: vmcheck3
-      distro: fedora/26/atomic
+      distro: fedora/27/atomic
   container:
-    image: registry.fedoraproject.org/fedora:26
+    image: registry.fedoraproject.org/fedora:27
 
 env:
   HOSTS: vmcheck1 vmcheck2 vmcheck3