bug#3973: cleanup view-mode usage in vc-resynch-window

Stefan Monnier <monnier@xxxxxxxxxxxxxxxx> writes:

  > > not sure what it's supposed to do... 
  > > But the comment (added in Apr 2000!) seems to say that it can be removed.
  > > Should it?
  > 
  > I don't know.  Someone needs to try it,

I have removed that code locally for a while and didn't see any
problem. But I don't explicitly use view-mode, so...
How about remove the code and see if someone sees a problem?