Send back SOCKS5 errors for all of the address related failures.

Cases that now send errors:
 * Malformed IP address (SOCKS5_GENERAL_ERROR)
 * CONNECT/RESOLVE request with IP, when SafeSocks is set
   (SOCKS5_NOT_ALLOWED)
 * RESOLVE_PTR request with FQDN (SOCKS5_ADDRESS_TYPE_NOT_SUPPORTED)
 * Malformed FQDN (SOCKS5_GENERAL_ERROR)
 * Unknown address type (SOCKS5_ADDRESS_TYPE_NOT_SUPPORTED)

Fixes bug 13314.
Merge remote-tracking branch 'yawning/bug13314'