**** Bank failures now total 140 in 2009 **** LOS ANGELES/NEW YORK, Dec 18 (Reuters) - OneWest Bank, formerly failed mortgage lender IndyMac, bought the assets of First Federal Bank after it was closed by U.S. regulators, in a deal that may bolster the case for private investment in banks. California's First Federal was one of seven U.S. lenders closed on Friday by regulators, bringing the total number of U.S. bank failures this year to 140. The 39 branches of First Federal -- formerly controlled by FirstFed Financial (FFED.PK) -- reopen on Saturday as OneWest Bank FSB. In addition to...