Update link for A.Shashua-Introduction_to_Machine_Learning.pdf
The original http variant will fail with "301 Moved Permanently".
Running 'get' on the new one will still fail with a message from arxiv
that "your client does not supply a proper User-Agent". I was unable
to make this go way by passing a --user-agent value to 'git annex
get'. The download works if git-annex uses curl, but that requires
changing annex.security.allowed-http-addresses.