xenapi: enforce filters after live-migration

Currently and network filters, including security groups, are
lost after a server has been live-migrated.

This partially fixes the issue by ensuring that security groups are
re-applied to the VM once it reached the destination, and been started.

This leaves a small amount of time during the live-migrate where the VM
is not protected. There is a further bug raised to close the rest of
this whole, but this helps keep the VM protected for the majority of the
time.

Fixes bug 1202266

(Cherry picked from commit: 5cced7a6dd32d231c606e25dbf762d199bf9cca7)

Change-Id: I66bc7af1c6da74e18dce47180af0cb6020ba2c1a