You may not like the Occupy D.C. encampment at McPherson Square, but it’s hard not to dig “Unified Tribes,” the new Thievery Corporation and Mr. Lif collaboration that extols the virtues of the movement while featuring D.C. prominently in the song’s video. If you want to hear the song live, the boys from Thievery are playing a three-night stand at the 9:30 Club in early January, but you might have to occupy the show — all the tickets are already gone.