[Stateless SG] Add test to check change stateful to stateless SG

This scenario test applies stateful SG to the VM, ensures that
connectivity is working fine and then detach SG from the vm, update it
to be stateless, attach again and ensures that connectivity is working
still fine.

Change-Id: I99cf5edf79a77f5940d28fa760e03b66d289be20
1 file changed