mirrormanager: try adding ftpsync as supplementary group

Right now mirrormanage isn't able to update mirrorlists because we have
a pre bitflip release thats not open to it. It gets a perm denied and
just crashes.

We use this pattern already in coreos where they have to deal with
ftpsync owned content (although it's writing there, not reading).

See: https://github.com/fedora-infra/mirrormanager2/issues/407

Signed-off-by: Kevin Fenzi <kevin@scrye.com>

roles/openshift-apps/mirrormanager/templates/deploymentconfig.yml

@@ -59,6 +59,8 @@ spec:
             - name: secrets
               mountPath: "/etc/mirrormanager-secrets"
               readOnly: true
+      securityContext:
+        supplementalGroups: [263]
 
       volumes:
         {{ common_volumes() }}