server/: Eliminate the remaining address-family-specific knowledge.

server/: Eliminate the remaining address-family-specific knowledge.

Outside of a few functions in `addrmap.c' and `servutil.c'.  Name
resolution now fails softly if it encounters an unexpected address
family (which can happen because of numeric conversion through
`getaddrinfo'), and the ADNS query flags are now set via the `aftab'.