[REG 3.3 -> 3.4] "Run qmake" is disabled

1. Create a new Qt Widgets Application project.
2. Close the project.
3. Open the project again.
4. Try to select "Build" -> "Run qmake" from the menu.
   You can't. It's disabled.
5. Click onto the project in Projects view.
6. Select "Build" -> "Run qmake" from the menu.
   Now it works.

"Run qmake" should always be enabled when a project is selected. When opening a project in an otherwise empty Creator, this project should be selected.

Found by Squish test tst_build_speedcrunch.