Rm on-prem Quay as registry target for discon OLM

Author: adellape

modules/olm-building-operator-catalog-image.adoc

@@ -11,7 +11,7 @@ registry that supports
 link:https://docs.docker.com/registry/spec/manifest-v2-2/[Docker v2-2]. For a
 cluster on a restricted network, this registry can be a registry that the cluster
 has network access to, such as the mirror registry created during the restricted
-network installation or an on-premise Quay Enterprise registry.
+network installation.
 
 [IMPORTANT]
 ====