Qmake: Do not show "Run qmake" needlessly

Do not show "Run qmake" in the menu right after Qt Creator starts up
with no project loaded.

Change-Id: I371734e902b518b6270ca14887db14c254237ba2
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

src/plugins/qmakeprojectmanager/qmakeprojectmanagerplugin.cpp

@@ -257,6 +257,8 @@ bool QmakeProjectManagerPlugin::initialize(const QStringList &arguments, QString
     connect(EditorManager::instance(), &EditorManager::currentEditorChanged,
             this, &QmakeProjectManagerPlugin::updateBuildFileAction);
 
+    updateRunQMakeAction();
+
     return true;
 }