This field isn't required by a worker and it's certainly not used by a
worker to listen on that specific interface. It also isn't required to
be set consistently and its use in-tree limited to the old load-balancing
script.
There's a bif called packet_source() which on a worker will provide
information about the actually used packet source.
Relates to zeek/zeek#2877.
This also installs symlinks from "zeek" and "bro-config" to a wrapper
script that prints a deprecation warning.
The btests pass, but this is still WIP. broctl renaming is still
missing.
#239