(Adds details on meeting, Alcoa (NYSE: AA - news) comment) NEW YORK, Aug 25 (Reuters) - The chairman of the U.S (Other OTC: UBGXF - news) . commodities regulator and an executive from aluminum producer Alcoa Inc will meet this week to discuss metals warehousing reform, a spokesman for the agency said on Tuesday. The meeting between U.S. Commodity Futures Trading Commission (CFTC) chairman Timothy Massad and Alcoa Chief Financial Officer Bill Oplinger will take place on Wednesday afternoon. The meeting comes as the aluminum company has ramped up public criticism of the regulator's intervention in the London... More