Do not touch get() calls on 'this' object.

Summary:
These calls are part of the implementation of the smart pointer itself
and chaning it is likely to be wrong.
Example:
  T& operator*() const { return *get(); }

Reviewers: djasper

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D3540

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@207525 91177308-0d34-0410-b5e6-96231b3b80d8