Remove dead buildbot link

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@220260 91177308-0d34-0410-b5e6-96231b3b80d8
Merge branch 'master' of http://llvm.org/git/libcxx
Merge branch 'master' of github.com:efcs/libcxx