Initialize the array with the "C++ way".

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@118302 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/Diagnostic.h b/include/clang/Basic/Diagnostic.h
index 55bda36..f9c211f 100644
--- a/include/clang/Basic/Diagnostic.h
+++ b/include/clang/Basic/Diagnostic.h
@@ -215,9 +215,7 @@
     unsigned char Values[diag::DIAG_UPPER_LIMIT/2];
 
   public:
-    DiagMappings() {
-      memset(Values, 0, diag::DIAG_UPPER_LIMIT/2);
-    }
+    DiagMappings() : Values() { }
 
     void setMapping(diag::kind Diag, unsigned Map) {
       size_t Shift = (Diag & 1)*4;