NETWORKER ALERT: network worker causing problems in 1.21

[Tim Penhey]

Hi folks,

There is something I'd like you to talk about while you are together in
Cape Town.

The new networker worker was added in 1.21, and is causing many problems
in the wild.

The lxcbr0 IP address is erroneously being chosen as the best address
for a machine.

The worker enumerates all the NICs and gets the addresses.  We need to
work out how to avoid selecting internal only addresses, like 'lxcbr0'
and 'virbr0' default addresses.  There are likely to be issues with
other things like additional other bridges or VLAN sub-interfaces.

I'd like you folk who understand networking more to work out some
heuristics that will at least get us unblocked.

Cheers,
Tim