core: fix handling firewall configuration for VM clones and DispVMs (#1032)
core: fix handling firewall configuration for VM clones and DispVMs (#1032)

There were two bugs:
1. Firewall configuration wasn't copied during qvm-clone (it is in
   separate file, so now it is included in vm.clone_disk_files).
2. Non-default firewall configuration wasn't stored in qubes.xml. This
   means that initially DispVM got proper configuration (inherited from
   calling VM), but if anything caused firewall reload (for example
   starting another VM), the firewall rules was cleared to default state
   (allow all).

Fixes qubesos/qubes-issues#1032

marmarek/qubes-core-admin,woju/qubes-core-admin,marmarek/qubes-core-admin,woju/qubes-core-admin,woju/qubes-core-admin,QubesOS/qubes-core-admin,woju/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,QubesOS/qubes-core-admin