Fix key bindings for VS 2010.

Set the default key-binding only in the text editor; the
global binding of ctrl-r,ctrl-f was already taken in VS 2010.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194482 91177308-0d34-0410-b5e6-96231b3b80d8