config: Make sure user doesn't mix IPv6 and IPv4

Checking code was there, sadly not correct, so it was possible to enter
one bindnet addr as IPv4 and second as IPv6. Fix is trivial.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>
config: Process broadcast option consistently

Broadcast option is global but in config set in interface section. When
more interfaces are defined, only broadcast from last section was used.

Solution is to use broadcast whenever at least one interface use
broadcast.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>