Follow redirects when generating index

[danbst]

Error: fetching the references of store path '/nix/store/k7j9ca2cnqy4c6wwbfp87mc8m0gbrzk4-r-YPmodel-1.3' failed
Caused by: request GET 'http://cache.nixos.org/k7j9ca2cnqy4c6wwbfp87mc8m0gbrzk4.narinfo' failed with HTTP error 302 Found
+ generating index: 00011 paths found :: 00197 paths not in binary cache :: 61164 paths in queue 
Error: fetching the references of store path '/nix/store/9svff0bq3n9b4npd1d7py8630cczib4p-r-zenplots-1.0.0' failed
Caused by: request GET 'http://cache.nixos.org/9svff0bq3n9b4npd1d7py8630cczib4p.narinfo' failed with HTTP error 302 Found
+ generating index: 00011 paths found :: 00198 paths not in binary cache :: 61163 paths in queue 
Error: fetching the references of store path '/nix/store/zb6kx35fnzp99wpwxmjdd7yg1q2qng1d-r-ZeBook-1.1' failed
Caused by: request GET 'http://cache.nixos.org/zb6kx35fnzp99wpwxmjdd7yg1q2qng1d.narinfo' failed with HTTP error 302 Found
+ generating index: 00011 paths found :: 00199 paths not in binary cache :: 61162 paths in queue 

I'm not sure if this is OK or not. And what to do to stop it.

[bennofs]

302 is a redirect, so I guess we should follow it? Looks like a bug to me. Probably something changed in s3/cloudfront that triggers it now.