Automation: Fix test_vpc_network_pfrules.py

Need to wait VM to boot up before stop the VR.

Also test 4 is identical to test 3, fix it.
fix CLOUDSTACK-3591 add usage recording for VM snapshots

Conflicts:

	plugins/hypervisors/xen/src/com/cloud/hypervisor/xen/resource/CitrixResourceBase.java
	server/src/com/cloud/vm/snapshot/VMSnapshotManagerImpl.java
	setup/db/db/schema-410to420.sql