Remove the policy checking for request_host_vmotion_enabled.

There are events request_host_enable_vmotion and request_host_disable_vmotion defined in db/fixtures/miq_event_definitions.csv.
But request_host_vmotion_enabled is not a defined event.

app/models/host.rb

@@ -487,7 +487,7 @@ def disable_vmotion
   def vmotion_enabled?
     msg = validate_vmotion_enabled?
     if msg[:available] && respond_to?(:vim_vmotion_enabled?)
-      check_policy_prevent("request_host_vmotion_enabled", "vim_vmotion_enabled?")
+      vim_vmotion_enabled?
     else
       _log.warn("Cannot check if vmotion is enabled because <#{msg[:message]}>")
     end