[Vcloud] Server reset instance vars after save

New networking support needs to reset the stored update value after a save is completed

lib/fog/vcloud/models/compute/server.rb

@@ -261,6 +261,7 @@ module Fog
           @update_password = nil
           @update_cpu_value = nil
           @update_memory_value = nil
+          @update_network = nil
           @name_changed = false
           @description_changed = nil
         end