[MERGE] Speed up blackbox.test_cat by 2 seconds

[Andrew Bennetts]

Alexander Belchenko wrote:
> Alexander Belchenko has voted -1.
> Status is now: Vetoed
> Comment:
> I'm sorry, but avoiding subprocess is wrong thing.
> 'bzr cat' should be tested in subprocess on win32, otherwise
> it's hard to test mangling of line-endings on windows.
> 
> Either make it conditional depending on platform,
> or make other call for bzr commands without invoking subprocess.
> 
> But in current form: -1 from me.

Fair enough, let's leave it as is then.  Instead I'll make a patch to add
comments about this; I had no idea from reading the code that checking the
output in the face of win32 line-ending mangling was the intent.

Thanks for information!

-Andrew.