Add allow_targeted_refresh? to Vmware InfraManager

While not actually used by the VMware streaming refresh worker, not
having allow_targeted_refresh? defined meant that any e.g. user automate
code which queued a `vm.refresh_ems` would end up actually executing a
full refresh and restarting the refresh worker's collector thread.

Adding allow_targeted_refresh? will queue up a simple target which will
be ignored by the refresh worker since we are refreshing from
WaitForUpdatesEx directly.

Author: agrare

app/models/manageiq/providers/vmware/infra_manager.rb

@@ -302,6 +302,10 @@ def streaming_refresh_enabled?
       true
     end
 
+    def allow_targeted_refresh?
+      true
+    end
+
     def queue_name_for_ems_operations
       queue_name
     end