[MERGE] Exception when pulling from a location

[Andrew Bennetts]

John Arbash Meinel wrote:
[...]
> > If we were repeating the same operation and hoping for different
> > results, I would agree.  But it's possible that attempting to open a
> > branch at a URL would succeed where attempting to open a bundle at that
> > URL would fail.
> > 
> > Aaron
> 
> So this is "could not connect" not "no such file". Or put another way
> NoSuchHost versus NoSuchFile.
> 
> I think the chances that you would get a *connection* failure (not a
> permission failure, not etc) and have it succeed the second time is very
> rare.
> 
> Specifically at this point we *are* doing the same thing twice. Namely,
> we are *connecting*.

Right, I agree with John.  It's not that a specific operation is failing and
that a different one might succeed, it's that establishing the connection at all
is failing.  Perhaps the docstring of ConnectionError should be clarified if
this isn't obvious?  (but I wouldn't block the patch on that!)

-Andrew.