Fix scala dependency 302 error

The scala library download was returning a '302 Found' response when the server loads the libraries.
This PR changes the URL to the one being redirected.
A more robust solution would be to follow redirects in the HTTP response headers, but this will do for now.

See my comment here: https://github.com/MrTJP/ProjectRed/issues/403#issuecomment-40309244
This addresses issue https://github.com/MinecraftPortCentral/MCPC-Plus/issues/975