CLOUDSTACK-1192: GetVmDiskStatsCommand return null as disk I/O statistics does not support xen/vmware
(cherry picked from commit 3121133c03c4db30c9bc0a3a5546e19678b2ee76)
CLOUDSTACK-2319: fix incorrect account_id in event table for Revoke SecurityGroupRule commands
(cherry picked from commit d9ba234d6c032aeb2ba04d4e6be0502de8a4efd9)
CLOUDSTACK-4566: fix incorrect values in resource_count table for resource limitation

There are three issues in resource_count table
(1) expunge a vm, the public_ip decreases and becomes -1 in basic zone.
(2) recover a vm, the volume increase.
(3) restore a vm, the volume decrease.