CLOUDSTACK-4289, CLOUDSTACK-4290, CLOUDSTACK-4291 : Check for null when populated UUID while listing usage records.
Filed CLOUDSTACK-4299 to make these entities always available.

Conflicts:
	server/src/com/cloud/api/ApiResponseHelper.java
CLOUDSTACK-4286. Add one more check for validating vlanrange parameter with "dedicateGuestVlanRange" API