fix menu timer in TwoPartSelection

stepmania/src/ScreenSelectMusic.cpp

@@ -868,6 +868,11 @@ void ScreenSelectMusic::MenuStart( const InputEventPlus &input )
 			StartTransitioningScreen( SM_BeginFadingOut );
 		}
 	}
+	else // !finalized.  Set the timer for selecting difficulty and mods.
+	{
+		m_MenuTimer->SetSeconds( 25 );
+		m_MenuTimer->Start();
+	}
 }