bug#1806: dired-pop-to-buffer in wrong place

[Stefan Monnier]

>> Showing *Messages* out of the blue is definitely not a feature.
>> IOW It doesn't look correct to me.

> It's bécasse:
[..]
> AFAIK there are no general Emacs window-handling features to do any of
> this in any more sophisticated fashion.

I know why the code gives this result.  But still, result is not good.
I think it's better to end up with


   +----------------------------------------------------------+
   |                                                          |
   |                                                          |
   |                   *scratch*                              |
   |                                                          |
   +----------------------------------------------------------+
   |                                                          |
   |                                                          |
   |                   *calendar*                             |
   |                                                          |
   +----------------------------------------------------------+

It may be suboptimal, but at least it doesn't end up with a weird window
arrangement displaying some randomly chosen old buffer.  It's easy for
the user to hit C-x 3 before running calendar, if she doesn't like
this behavior; much easier than trying to fix the mess of the
current code, when you're not happy with its choices.


        Stefan