[REGRESSION] bzr 1.17 does not use _knit_load_data compiled extension

[Andrew Bennetts]

Andrew Bennetts wrote:
[...]
> > _knit_load_data_c was renamed to _knit_load_data_pyx by Vincent in bzr.dev
> > revno 4472 but Vincent did not update all imports. At least not in 1.17.
> > 
> > I don't know is it critical for performance (I suppose -- yes), but it does
> > not sound right for me anyway.
> 
> Ouch, yes.  That does seem to be case.  I think that's a critical bug worth
> making a 1.17.1 release for.  Thanks for catching that!

I've landed a fix in bzr.dev r4574.  If someone does go ahead with making a
1.17.1 (Martin maybe?  I think jml is unavailable for RM duties this week) then
they should cherrypick that.