• Remove unused but set ssize in shutdown_send_sigpipe
• Add #ifdef TEST_SEQ_PACKET_SOURCE_ADDRESS` for untestable code because FreeBSD doesn't have a means to map source addresses for SEQ_PACKET AF_UNIX sockets (paraphrased). Put pathname variable under the #ifdef to mute another unused but set variable warning

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division