This patch disallows deleting / modifying system defined guest OS mappings

Local env
1. Create user defined mapping
2. Delete / modify user defined mapping. Should pass
3. Delete / modify system defined mapping. Should fail

Signed off by :- Nitin Mehta<nitin.mehta@citrix.com>
CLOUDSTACK-6519 [Hyper-V] while adding VM to Network it should throw error when it is in running state