[OpenCL][Bug 10573] Don't set CXXOperatorNames flag
The flag CXXOperatorNames was overwritten unconditionally
after being set for OpenCL.
There seems to be no necessity to set it, so removing the line.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@298709 91177308-0d34-0410-b5e6-96231b3b80d8