Renaming kit does not update the kit's name in proposed build directories

1. Start Creator with empty settings.
2. Have a kit configured.
   The default kit from a Qt version in PATH is sufficient.
3. Start creating a new project and proceed to the "Kit Selection" page of the wizard.
4. Click on "Details".
   You'll see that the proposed build directories contain the kit's name, e.g. "/tmp/build-untitled-Desktop-Debug" for the kit "Default".
5. Click on "Manage..."
6. Rename the kit and click "OK".
   The kit name in the wizard updates but the directories remain the same:
   
7. Click "Cancel".
8. Repeat steps 3 and 4.
   Now the proposed directories were updated.

The directories should only be left unchanged if the user edited them manually. The automatically generated paths should be updated together with the kit name.