CMake: Quieten soft-assert on small project loads

The directory tree scanner and the project parsing work independently of
each other. Add logic to combine these two sets of results into one
parsing state.

Change-Id: I46e94f0e866b40ee7225235c536c742cecf11b45
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/plugins/cmakeprojectmanager/cmakeprojectmanager.cpp

@@ -152,6 +152,5 @@ void CMakeManager::rescanProject(Project *project)
     if (!cmakeProject || !cmakeProject->activeTarget() || !cmakeProject->activeTarget()->activeBuildConfiguration())
         return;
 
-    cmakeProject->scanProjectTree();
-    cmakeProject->runCMake(); // by my experience: every rescan run requires cmake run too
+    cmakeProject->runCMakeAndScanProjectTree();// by my experience: every rescan run requires cmake run too
 }