[analyzer] Teach DeadStoreChecker to look though BO_Comma and disregard the LHS.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@180579 91177308-0d34-0410-b5e6-96231b3b80d8
Objective-C: This is a small modification to my
patch -n r180198.
When reporting on missing property accessor implementation in
categories, do not report when they are declared in primary class,
class's protocol, or one of it super classes or in of the other
categories. // rdar://13713098


git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@180580 91177308-0d34-0410-b5e6-96231b3b80d8