fix coin/join logic

stepmania/src/GameState.cpp

@@ -1012,3 +1012,10 @@ void GameState::StoreRankingName( PlayerNumber pn, CString name )
 		*aFeats[i].pStringToFill = name;
 	}
 }
+
+bool GameState::UsingPremiumAndPaying()
+{
+	return
+		(PREFSMAN->m_bVersusForOneCredit || PREFSMAN->m_bDoubleForOneCredit) &&
+		PREFSMAN->m_iCoinMode == COIN_PAY;
+}