[REG 4.2 -> 4.3] qbs: Project tree does not show "name" of qbs-project

1. Open a qbs-based project.
2. Show the "Projects" view.
   The project's root-node has the name of the project's qbs-file.
3. In the qbs-file, add the line:

   name: "Bug demo"
   

4. Save the qbs-file.
   Nothing happens.

The project's root-node should be renamed to "Bug demo". In Creator 4.2, this used to work correctly.

Found by Squish test tst_opencreator_qbs