Update url for stanford rare word(rw).zip
Update url for stanford rare word(rw).zip

Summary:
The url for stanford rare word is no longer accurate as of date.
Closes https://github.com/facebookresearch/fastText/pull/80

Reviewed By: piotr-bojanowski

Differential Revision: D3900224

Pulled By: EdouardGrave

fbshipit-source-id: e22d48d0f5da2d540507f29e4b367a62c215256c

facebookresearch/fastText,magicBus234/fastTextJob,facebookresearch/fastText,facebookresearch/fastText,magicBus234/fastTextJob,magicBus234/fastTextJob,facebookresearch/fastText,facebookresearch/fastText,magicBus234/fastTextJob,facebookresearch/fastText