[analyzer] Refactor RetainReleaseChecker to go through a function call
to set/get/remove the RefBinding.

No functional change here. Having these setter and getter methods will
make it much easier when replacing the underlining representation of
RefBindings (I just went through the exercise). It makes the code more
readable as well.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@161820 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed