Mocked for millions of dollars in Big Dig cost overruns, the Turnpike Authority has one cost-saving measure solidly in place: charging thirsty workers for sipping at the office water cooler. The Turnpike is sticking by the no-free-water policy even as ax-wielding Transportation Secretary John Cogliano has agreed to pick up the bubbler tab this month for another state agency – MassHighway. Cogliano made the call after learning that MassHighway rank-and-file were paying to drink up, while brass at his Executive Office of Transportation were hydrating for free. "It came to his attention that some people in other departments had water...