The best thing about the release this week of the new/old Michael Jackson song “This Is It”? That Paul Anka might finally get some Grammy cred.  The worst thing? That it would be for this forgettable, fizz-less trifle.  The Grammy-less Anka, the wizard behind such gems as the theme music for “The Tonight Show with Johnny Carson” and Frank Sinatra’s signature “My Way” (Anka wrote the English lyrics), quickly addressed the Jackson estate this week, hours after “This Is It” was released online, to claim his co-writing credit.