unix/socket.c: don't send to a socket with pending_send.
unix/socket.c: don't send to a socket with pending_send.

process_fds() would send to a socket that had a pending send already, resulting in
socket.c:1663: INSIST(!sock->pending_send) [BIND 9.3.4, still present in 9.4.1-P1]

See http://bugs.debian.org/430065

Addresses-Debian-Bug: 430065
Signed-off-by: LaMont Jones <0ab8dc438f73addc98d9ad5925ec8f2b97991703@debian.org>

tjaalton/bind9,tjaalton/bind9,tjaalton/bind9,tjaalton/bind9,tjaalton/bind9,tjaalton/bind9