bug#16284: 24.3.50; blank column shown with scroll bar configuration changes

[martin rudalics]

>>> Steps to reproduce:
>>>
>>> 1. $ emacs -Q -D &
>>> 2. M-x scroll-bar-mode RET
>>> 3. M-x scroll-bar-mode RET
>>>
>>> Then you'll see a blank column to the right of the scroll bar.
>> Hopefully fixed now.  Please try again.
>
> Emacs still thinks the scroll bars are displayed when it is started
> with -D: step 2 says "Scroll-Bar mode disabled", although the scroll
> bar was not shown before that.

That's a different issue.  I only fixed the blank column part (which I
couldn't even observe on Windows).

I don't know how -D is processed internally and what its semantics wrt
scrollbars should be.  What's probably needed is to either disable
scroll-bar-mode or reset the `vertical-scroll-bar' parameter of the
initial frame.

martin