[analyzer] Remove extra assignment that actually lost a few of the assumptions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@132614 91177308-0d34-0410-b5e6-96231b3b80d8

lib/StaticAnalyzer/Checkers/CStringChecker.cpp

@@ -737,7 +737,6 @@ void CStringChecker::evalCopyCommon(CheckerContext &C,
       return;
 
     // Ensure the buffers do not overlap.
-    state = stateNonZeroSize;
     state = CheckBufferAccess(C, state, Size, Dest, Source,
                               /* FirstIsDst = */ true);
     if (Restricted)