QFileSystemModel: Plug leak on file renaming

In setData(), the old code both called Private::addNode(),
which creates a QFileSystemNode and adds it to the parent's
QHash of children, and also re-purposed the old node by
taking it out of the children hash, adjusting the fileName
member of the node and putting it back into the children
hash under the new name, where it would overwrite the node
just added under the same (new) name in addNode(). Since
the hash stores naked pointers, no-one deletes the node
that was put into the hash first.

Fix by dropping the addNode() call completely.

Change-Id: I0c37917fd0ffd74716393786c69b5bb172aa372e
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

src/widgets/dialogs/qfilesystemmodel.cpp

@@ -885,7 +885,6 @@ bool QFileSystemModel::setData(const QModelIndex &idx, const QVariant &value, in
         QFileSystemModelPrivate::QFileSystemNode *parentNode = indexNode->parent;
         int visibleLocation = parentNode->visibleLocation(parentNode->children.value(indexNode->fileName)->fileName);
 
-        d->addNode(parentNode, newName,indexNode->info->fileInfo());
         parentNode->visibleChildren.removeAt(visibleLocation);
         QFileSystemModelPrivate::QFileSystemNode * oldValue = parentNode->children.value(oldName);
         parentNode->children[newName] = oldValue;