Fix C++0x incompatibility. The signature of std::make_pair<> changes from:

  template <class T1, class T2> pair<T1,T2> make_pair(const T1&, const T2&);
to
  template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);
so explicitly specifying the template arguments to make_pair<> is going to break
when C++0x rolls through. Replace them with equivalent std::pair<>. Patch by
James Dennett!

llvm-svn: 126256