[REG 4.5 -> 4.6] No valid kits for qmlproject found (Run button disabled after opening a qmlproject)

1. Have a kit using Qt 5.9.4.
2. Open a qmlproject.
   I used qtdeclarative/examples/quick/demos/samegame/samegame.qmlproject from the sources of Qt 5.9.4.
3. Go to Projects mode.
   Creator will claim that the are no valid kits. You are not able to run the project.

I don't see a reason why it should not be possible to run the project on the existing kit. Creator 4.5 does this without any obvious problems.