Fix the IPv6 case of tor_ersatz_socketpair

In get_local_listener which is used by tor_ersatz_socketpair, sin6_family is currently being set to AF_INET in the IPv6 case when AF_INET6 should be used instead.

This code was introduced in commit 9b24609a from this past August, so this is not a brand-new problem.

I tested this on my OpenBSD box by forcing an IPv6 socket to be used for tor_ersatz_socketpair and running the test suite. There is a test in the test suite that tests tor_ersatz_socketpair: it (of course) fails using the current AF_INET code but it passes when using AF_INET6 instead.

PR to follow to change AF_INET to AF_INET6 in the IPv6 case.

Trac:
Username: kjak