Here’s how Raiders made sure ‘Hard Knocks’ wasn’t a distraction

If there’s an afterlife, somewhere on Tuesday night Al Davis was smiling through gritted teeth and pumping his fist after the Raiders one-upped the NFL establishment again. And make no mistake, the final episode of HBO’s “Hard Knocks” was the culmination of a nearly two-month victory march for the Silver & Black.

The Raiders couldn’t stop NFL Films’ cameras from invading their training camp for the docuseries, but they made damn sure they stifled the process. HBO was left with much more immaterial footage than usual because, unlike every other team documented, the Raiders cloaked their player cuts — i.e. the most compelling drama — in secrecy. All but one of the more than 50 players who were…