MFC r223626:

Compare port numbers correctly. They are stored by SRCPORT()
in host byte order, so we need to compare them as such.
Properly compare IPv6 addresses as well.

This allows the, by default, 8 badaddrs slots per address
family to work correctly and only print sendto() errors once.

The change is no longer applicable to any latest upstream versions.

Approved by: roberto
Sponsored by: Sandvine Incorporated