Don't play the Start sound in SM_BeginFadingOut. It might

have been triggered by something that just played a sound,
or the screen might want to play a different sound.  It's
not SM_BeginFadingOut's job to play a sound.

(fixes double-start sound when "next screen" options are
selected from context menus in ScreenOptionsManage*)

stepmania/src/ScreenOptionsMemoryCard.cpp

@@ -127,6 +127,7 @@ void ScreenOptionsMemoryCard::ProcessMenuStart( const InputEventPlus &input )
 		bool bSuccess = MEMCARDMAN->MountCard( PLAYER_1, dev );
 		if( bSuccess )
 		{
+			SCREENMAN->PlayStartSound();
 			this->BeginFadingOut();
 		}
 		else