It has looked as though things were over for Dwayne “The Rock” Johnson several times over the years. He’d have a run as action hero, string together some flops, seem on the way to Van Damme Land. You start to see a big stack of fresh WWE credits on his resume when that happens. Then bam, “The Game Plan” comes along, or a supporting part in “Fast/Furious -XXII” and he’s back as a leading man. For a bit. “Snitch” has him playing a rough-trade dad who resolves to do undercover informant work to lessen his drug-connected son’s sentence from the Feds. He’s got Susan Sarandon, Benjamin Bratt and Barry Pepper in supporting roles, but a stunt-man turned director with middling credits. And it’s a February movie — low expectations. But there’s always hope when The Rock is in the house. Someday, he’ll score another film as amusing, two-fisted and fun as “The Rundown.”