[analyzer] Make VLA checker taint aware. 

Also, slightly modify the diagnostic message in ArrayBound and DivZero (still use 'taint', which might not mean much to the user, but plan on changing it later).

llvm-svn: 148626
diff --git a/clang/lib/StaticAnalyzer/Checkers/DivZeroChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/DivZeroChecker.cpp
index b9ed384..9f2f515 100644
--- a/clang/lib/StaticAnalyzer/Checkers/DivZeroChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/DivZeroChecker.cpp
@@ -37,10 +37,10 @@
                                CheckerContext &C) const {
   if (ExplodedNode *N = C.generateSink(StateZero)) {
     if (!BT)
-      BT.reset(new BuiltinBug(Msg));
+      BT.reset(new BuiltinBug("Division by zero"));
 
     BugReport *R =
-      new BugReport(*BT, BT->getDescription(), N);
+      new BugReport(*BT, Msg, N);
 
     R->addVisitor(bugreporter::getTrackNullOrUndefValueVisitor(N,
                                  bugreporter::GetDenomExpr(N)));