Periphery lags as European shares post small gains ahead of Fed

* FTSEurofirst 300 up 0.2 pct * BBVA leads euro zone bank selloff after result miss * Traders say investors more cautious after AQR * Fugro tumbles 26 pct after cancelling payout By Francesco Canepa LONDON, Oct 29 (Reuters) - Southern European shares lagged small gains in pan-European indexes on Wednesday as weak results from heavyweight bank BBVA offset optimism ahead of a Federal Reserve's policy announcement. Spanish bank BBVA fell 4.1 percent as it reported a lower-