Fix removing unnamed quick tests...

...this was wrong especially when closing (the last) open project
that contained unnamed quick tests.

Change-Id: I6d030b6219d9f397a6ffb51a985ef4147eebec8a
Reviewed-by: David Schulz <david.schulz@theqtcompany.com>
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>