The MBTA is bringing back former general manager Dan Grabauskas as a $30,000-a-month commuter rail consultant, a year after he resigned as head of a Honolulu's rapid transit agency, officials said today.Grabauskas, who was was forced out as the T's GM in 2009 by Gov. Deval Patrick, will be responsible "overall for the management and supervision" of the T's commuter rail system, which is currently operated by the French company Keolis.