Fixed use of an uninitialized variable.

llvm-svn: 47691
diff --git a/clang/Analysis/GRSimpleVals.cpp b/clang/Analysis/GRSimpleVals.cpp
index b3e11dd..95a9f85 100644
--- a/clang/Analysis/GRSimpleVals.cpp
+++ b/clang/Analysis/GRSimpleVals.cpp
@@ -30,7 +30,7 @@
   Out << "[CHECKER] " << msg;
   msg = Out.str().c_str();
   
-  bool isFirst;
+  bool isFirst = true;
   unsigned ErrorDiag;
   
   for (; I != E; ++I) {