C++: fix possible nullptr deref.

Pointed out by the clang static analyzer.

Change-Id: I69ab89e651cbcb13606d5d93a05f629172cbd9e0
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/libs/3rdparty/cplusplus/Bind.cpp

@@ -1884,7 +1884,7 @@ bool Bind::visit(SimpleDeclarationAST *ast)
             const ExpressionAST *initializer = it->value->initializer;
             if (!initializer && declaratorId)
                 translationUnit()->error(location(declaratorId->name, ast->firstToken()), "auto-initialized variable must have an initializer");
-            else {
+            else if (initializer) {
                 unsigned startOfExpression = initializer->firstToken();
                 unsigned endOfExpression = initializer->lastToken();
                 decl->setInitializer(asStringLiteral(startOfExpression, endOfExpression));