bug#34614: 26.1.92; When reading input in mini-buffer, message to each area overide the input prompt

[martin rudalics]

> Steps to reproduce the bug:
> 1. start emacs with emacs -Q
> 2. M-x global-auto-revert-mode
> 3. Open a test file with emacs
> 4. M-x find-file, it will prompt and read file name
> 5.  modify the test file with other tool and save the file
> 6. emacs will revert the file and print a message like "Reverting buffer xxx”.
> 7. the find-file ui will not come back.

It comes back here with the next character I type.  I have no idea how
to fix this.  At least sitting for 'minibuffer-message-timeout' in
'auto-revert-handler' when the minibuffer depth is greater zero won't
cut it - the message gets cleared immediately and minibuffer contents
are restored.  Some 'sit-for' snafu, I suppose.

martin, trying to resend this