I will not go quietly, I’ll tell you what I think, Phil Vassar declares on “This Is My Life,” the leadoff track from his fourth studio album. He then proceeds to say . . . not a whole lot, except that he’s mad about high gas prices. The rest of Prayer of a Common Man is just as frustratingly tame, both musically and lyrically. While it’s near-impossible for a polished pro like Phil—one of Music City’s best tunesmiths, and a singer of increasing assurance—to record an outright dud, it nonetheless feels like a retreat after 2004’s relatively rollicking Shaken Not Stirred.