A Tracy man was indicted by a federal grand jury in connection with a cyberattack on an East Bay water treatment plant that endangered the region’s water supply, the U.S. District Attorney’s Office Northern District of California announced.  Rambler Gallo, 53, was charged with intentionally uninstalling the main operational and monitoring systems for the Discovery Bay Water Treatment Facility, which treats water and wastewater for about 15,000 residents in the Contra Costa County community of Discovery Bay, federal prosecutors said in a statement on Friday.  Gallo’s alleged actions caused “a threat to public health and safety,” United States Attorney Ismail Ramsey and FBI San Francisco Special Agent in Charge Robert Tripp said in a joint statement.