[Merge][#301969]Give proper error message for diff with non-existent dotted revno

[Aaron Bentley]

bb:approve

Marius Kruger wrote:
> 2008/12/1 Aaron Bentley <aaron at aaronbentley.com
> <mailto:aaron at aaronbentley.com>>
> 
>     Aaron Bentley has voted resubmit.
>     Status is now: Resubmit
>     Comment:
>     It doesn't make sense to use NULL_REVISION when the revno is not
>     supplied.  That is a specific revision-- it doesn't mean "unspecified".
> 
> I'm sorry about that, while trying to figure out whats wrong I got a
> deprecation warning,
> since some code down the line used the null revid. Now that we give the
> proper exception I don't see that warning any more.
> 
> updated patch attached.
> 
> thanks a lot for looking at this
> marius
>