Run QMake, static_cast not qobject_cast

Change-Id: Ib9be214838d8e10dbd1a870d894bf7485265a43e
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>

src/plugins/qt4projectmanager/qt4projectmanager.cpp

@@ -377,10 +377,7 @@ void Qt4Manager::runQMake(ProjectExplorer::Project *p, ProjectExplorer::Node *no
         !qt4pro->activeTarget()->activeBuildConfiguration())
         return;
 
-    Qt4BuildConfiguration *bc = qobject_cast<Qt4BuildConfiguration *>(qt4pro->activeTarget()->activeBuildConfiguration());
-    if (!bc)
-        return;
-
+    Qt4BuildConfiguration *bc = static_cast<Qt4BuildConfiguration *>(qt4pro->activeTarget()->activeBuildConfiguration());
     QMakeStep *qs = bc->qmakeStep();
     if (!qs)
         return;