CLOUDSTACK-3951: Don't require SSH access to KVM nodes when cancelling maintenance
recalculate the capacity after overcomit change.

Conflicts:
	server/src/com/cloud/capacity/CapacityManager.java
	server/src/com/cloud/capacity/CapacityManagerImpl.java
	server/src/com/cloud/resource/ResourceManagerImpl.java
	server/src/com/cloud/vm/VirtualMachineManagerImpl.java