OSDOCS: Removes cluster-admin reference.

Author: EricPonvelle

modules/support-submitting-a-case.adoc

@@ -11,10 +11,9 @@
 
 .Prerequisites
 
-* You have access to the cluster as a user with the `cluster-admin` role.
 * You have installed the OpenShift CLI (`oc`).
 * You have a Red Hat Customer Portal account.
-* You have a Red Hat standard or premium Subscription.
+* You have access to {cluster-manager-url}.
 
 .Procedure