connector: Check for POLLHUP on in_fd
POLLHUP needs to be checked on in_fd, which may be a pipe.
A pipe in Linux signals EOF through POLLHUP (see:
Without checking POLLHUP, a client could spin up indefinetely
Signed-off-by: Alberto Aguirre <email@example.com>
Reviewed-by: Andreas Schneider <firstname.lastname@example.org>