It seemed just a bit odd when Jerry Brown, elected to his second go-’round as governor on a strong environmental program, almost immediately abandoned this state’s least expensive and most productive clean-air and environmental preservation law. Well, OK, he didn’t completely ax the Williamson Act, a 1965 law that assures 15 million acres of open California land will not be built over for at least 20 years. Nope, he left $1,000 in the program, just like predecessor Arnold Schwarzenegger did the previous year. Under the Williamson Act, named for former Republican state legislator John Williamson, who thought up the idea …