Fixed SelectionDAGBuilder.h C++ filetype declaration to use the canonical C++ instead of c++.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188203 91177308-0d34-0410-b5e6-96231b3b80d8
Revert r188188 and r188200.

In order to appease people (in Apple) who accuse me for committing "huge change" (?) without proper review. 

Thank Eric for fixing a compile-warning. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188204 91177308-0d34-0410-b5e6-96231b3b80d8
Add editor C++ filetype declaration no functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188205 91177308-0d34-0410-b5e6-96231b3b80d8