[MERGE] fix blackbox failures when run from windows executable

[Andrew Bennetts]

John Arbash Meinel wrote:
[...]
> I think you are fixing the wrong half of it. I would rather you change:
> 
> self.assertEqual(os.path.realpath('blah', 'blah', 'blah'),
> 		 ...local_abspath('blah'))
> 
> to be
> 
> self.assertEqual(osutils.realpath('blah', 'blah', 'blah'),
> 		 ...local_abspath('blah'))

Good idea.

[...]
> 
> So... local_abspath() is meant to be used because Transports work only
> in terms of URLs, and sometimes we need to open something up on disk,
> and doing open('file:////') doesn't work.
> The only callers are in workingtree.py and workingtree_4.py
> 
> One could argue about it returning a "C:\Path" rather than "C:/Path",
> but ATM I prefer it returning "C:/Path" to be consistent with all other
> paths inside bzrlib.

I agree.

-Andrew.