Ivy completion buffer is broken when created with active y-or-n-p prompt

[kurnevsky]

Try to execute the following example:

(progn
  (run-with-timer 1 nil (lambda () (ivy-completing-read "b" '("a" "b"))))
  (y-or-n-p "a"))

When ivy buffer popups it can't accept any input - all keys are undefined.

[abo-abo]

Thanks, please test.

I think the situation is quite rare, so the "fix" is to cancel y-or-n-p. Unfortunately, ivy-read has to be restarted manually.