Auto merge of #45734 - kennytm:ci-fix-centos-broken-link, r=alexcrichton
ci: Fix broken link in `build-powerpc64le-toolchain.sh`
r? @rust-lang/infra
This is just an emergency fix to keep bors running for another week. I think the numbers will be broken soon. Can we verify if this statement is still true later?
> First, download the CentOS7 glibc.ppc64le and relevant header files.
> (upstream ppc64le support wasn't added until 2.19, which el7 backported.)