LOS ANGELES (Reuters) - Texas rock trio ZZ Top has parted ways with the manager who helped form the band in 1969, according to a statement issued on Sunday. In addition to splitting with Bill Ham, the band has also ended its tenure at RCA Records, 14 years after signing a five-album contract reportedly worth $30 million. ZZ Top's most recent album, "Mescalero," spent just three weeks on the Billboard 200 in 2003. Its stint at RCA, beginning with 1994's "Antenna," failed to match its run at Warner Bros. Records, where it recorded the biggest hit of its career, 1983's...