. leave out dead code from device.c

. leave out dead code from device.c
. don't loop doing a receive() after sendrec() - chance of recovering is not
  high, and can lead to receive()ing a notify() (which can't happen in sendrec()),
  which is terrible
. return status from device when DEV_CANCEL is done on a signal; hardcode EAGAIN to
  become EINTR though