netinet: Disallow connections to INADDR_ANY

Previously connect() or sendto() to INADDR_ANY reached some socket bound
to some host interface address. Although this was intentional it was an
artifact of a different era, and is not desirable now.

In 417b35a97b76 markj added support to disallow connect() to INADDR_ANY.
Take the next logical step and disable it by default.

PR: 280705
Reviewed by: markj, jhb, zlei
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D47740