Keep nfv

I added both `:close()` and `:reconfig()` methods to Intel10g (had to fix a little on app.lua for the second one).

The `:close()` is still missing deallocations, but the `:reconfig()` works on the "diff_vlans => same_vlan" test.
there's much trial and error there, as it's not clear when it's needed to suspend chip-wide tx/rx to reprogram one queuepool.  the 'reenabling' is about leaving other things as they were.  so far it seems not to be needed, so it could be removed.  if needed i agree it could be better on a separate function.