More tweakage for STR #1313, mainly to remove the IPv4-over-IPv6 address

More tweakage for STR #1313, mainly to remove the IPv4-over-IPv6 address
support and to properly handle addresses that can't be bound.

cups/http-addr.c:
    - httpAddrEqual(): Drop support for IPv4-over-IPv6 addresses.
    - httpAddrLocalhost(): Drop support for IPv4-over-IPv6
      addresses.

cups/http-addrlist.c:
    - httpAddrGetList(): Support NULL hostname which maps to the
      passive listener ("any") address(es), and add different
      localhost fallback code.

scheduler/conf.c:
    - get_address(): Drop deffamily and defaddress arguments, and
      simplify to use httpAddrGetList() exclusively for all
      lookups.
    - read_configuration(): Update to use new get_address()
      parameters.

scheduler/listen.c:
    - cupsdPauseListening(), cupsdResumeListening(): Ignore
      listen sockets < 0.
    - cupsdStartListening(): Don't abort because of a
      socket/listen error, drop IPv4-over-IPv6 support, drop
      fallback to IPv4 after failed IPv6 socket on localhost/any
      addresses.

git-svn-id: svn+ssh://src.apple.com/svn/cups/cups.org/trunk@4773 7a7537e8-13f0-0310-91df-b6672ffda945