Fix crash on FlatModel::added with empty list

Change-Id: I6a5970eb9ccd76e730203c2d95dbd4e4dbb4af8a
Reviewed-by: hjk <hjk@theqtcompany.com>

src/plugins/projectexplorer/projectmodels.cpp

@@ -617,6 +617,12 @@ void FlatModel::added(FolderNode* parentNode, const QList<Node*> &newNodeList)
     qCDebug(logger()) << "FlatModel::added" << parentNode->path() << newNodeList.size() << "nodes";
     QModelIndex parentIndex = indexForNode(parentNode);
     // Old  list
+
+    if (newNodeList.isEmpty()) {
+        qCDebug(logger()) << "  newNodeList empty";
+        return;
+    }
+
     QHash<FolderNode*, QList<Node*> >::const_iterator it = m_childNodes.constFind(parentNode);
     if (it == m_childNodes.constEnd()) {
         if (!parentIndex.isValid()) {