CMake: Make sure a CMakeBuildConfiguration always has a CMakeBuildSystem

For this to work, we need to make sure no parsing is triggered before
the project is fully set up. Otherwise it would be QTCREATORBUG-23816
again...

Change-Id: If81f4c6b9c82283abdaa8a635f93ebe0bcaf8159
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildsystem.h

@@ -101,6 +101,8 @@ private:
     void handleParsingSucceeded();
     void handleParsingFailed(const QString &msg);
 
+    void wireUpConnections(const ProjectExplorer::Project *p);
+
     BuildDirManager m_buildDirManager;
 
     ProjectExplorer::TreeScanner m_treeScanner;