Un-revert r196358: "llvm-cov: Added support for function checksums."

And add the proper fix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196367 91177308-0d34-0410-b5e6-96231b3b80d8
Update email address.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196369 91177308-0d34-0410-b5e6-96231b3b80d8