Stale links (buildbot, llvm-cov) on https://llvm.org

Buildbot (http://lab.llvm.org:8011/) -> it is now
Buildbot (currently 502 Bad Gateway)
llvm-cov (http://lab.llvm.org:8080/coverage/coverage-reports/index.html)
-> ERR_CONNECTION_REFUSED

the website's accessible in the 'llvm-www' repository (
https://github.com/llvm/llvm-www ) if you want to fix them - any
commits there I think go live automatically