Don't insert items into the wrong row

This happened to work by chance, as QList::insert() would
gracefully handle out of bounds insertions.

Change-Id: I7ee1e645ed9a538946a509957ce5155641ffea1d
Reviewed-by: David Faure <david.faure@kdab.com>

tests/auto/other/qabstractitemmodelutils/dynamictreemodel.cpp

@@ -228,7 +228,7 @@ void ModelMoveCommand::doCommand()
             if (srcParent == destParent)
                 d = m_destRow - (m_endRow - m_startRow + 1);
             else
-                d = m_destRow - (m_endRow - m_startRow) + 1;
+                d = m_destRow;
         }
 
         foreach (const qint64 id, l)