this is fragile, slow as fuck, breaks constantly under high concurrency,
and completely unnecessary since ssh bypasses the stdio file descriptors
*anyway*. we do still check that we see ssh messages to ensure that none
of our subprocess handling messes with ssh's /dev/tty, but that's it now
Change-Id: Ib8e31e1999f813d07a27efc63a9d3454a9e4fcdd
eldritch horrors
59e364c2a8