Using "final" as a variable name is a bit confusing in C++11, so rename it.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@199526 91177308-0d34-0410-b5e6-96231b3b80d8
Use auto for readability. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@199527 91177308-0d34-0410-b5e6-96231b3b80d8