[PATCH] generaldelta: initialize basecache properly

[Sean Farley]

lopek at fb.com writes:

> I've resent the patch with a minimal test added.
>
> Btw. I cloned crew repo with generaldelta turn on and results were pretty impressive - manifest size went down from 19M to 4.1M. In this case generaldelta gives a lot more than everything what I've tried on the manifest level.

Just for reference, without your patch, generaldelta still compresses
the manifest for the crew repo down to 4.8M.