Fix "Assertion 'iNumTapsInRow > 0' failed" if attack notes happen to slip

into the data.  (They aren't generally used yet, and not recommended since
they may change significantly, but they occasionally end up in data, so let's
not crash.)

stepmania/src/Player.cpp

@@ -1061,8 +1061,12 @@ void PlayerMinus::UpdateTapNotesMissedOlderThan( float fMissIfOlderThanSeconds )
 		bool MissedNoteOnThisRow = false;
 		for( int t=0; t<m_NoteData.GetNumTracks(); t++ )
 		{
-			if( m_NoteData.GetTapNote(t, r).type == TapNote::empty) /* no note here */
-				continue; 
+			switch( m_NoteData.GetTapNote(t, r).type )
+			{
+			case TapNote::empty:
+			case TapNote::attack:
+				continue; /* no note here */
+			}
 			if( m_NoteData.GetTapNoteScore(t, r) != TNS_NONE ) /* note here is already hit */
 				continue;