Update CentOS 7 build to pull OpenSSL from GitHub instead of openssl.org (#17992)
Update CentOS 7 build to pull OpenSSL from GitHub instead of openssl.org (#17992)

Instead of using `git://git.openssl.org/openssl.git`, swap to the official
GitHub mirror at `https://github.com/openssl/openssl.git`. git:// is inheritly
insecure, and while we have additional protections in place as far as commit
hash checking, best to always pull dependencies from https:// wherever possible.
gravitational/teleport,gravitational/teleport,gravitational/teleport,gravitational/teleport,gravitational/teleport,gravitational/teleport