config: re-enable kola-openstack

The kola-openstack job is passing again, so lets re-enable the
job in the pipeline. There must have been some temporary issues
with Vexxhost.

See: #1061

This reverts commit e36f84e.

Author: marmijo

config.yaml

@@ -110,7 +110,7 @@ clouds:
       - "fedora-coreos-${STREAM}"
       - "https://compute.googleapis.com/compute/v1/projects/vm-options/global/licenses/enable-vmx"
   openstack:
-    test_architectures: [none]
+    test_architectures: [x86_64, aarch64]
 
 misc:
   versionary: true