dom0: populate unchanged firewall settings with previous values (#589)
dom0: populate unchanged firewall settings with previous values (#589)

Missed settings in new firewall configuration caused exception. In old qubes-manager (before #582 done) this exception silently broke saving operation, leaving user with progress bar windows infinitely...

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