ADT/Optional.h: Appease msvc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175626 91177308-0d34-0410-b5e6-96231b3b80d8
Whitespace.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175627 91177308-0d34-0410-b5e6-96231b3b80d8