Vasquez-Martinez v. Holder, 564 F.3d 712 (5th Cir. Apr. 2, 2009) (burden of production of evidence of aggravated-felony bar to cancellation of removal lies on noncitizen: "Second, neither Cisneros-Perez nor any case in this Circuit establishes the proposition that the initial burden of production of evidence that the alien is ineligible for discretionary relief lies with the government. Such a conclusion does not flow from the language of the statute or the concomitant regulation."), citing 8 U.S.C. 1229a(c)(4)(A)(i); 8 C.F.R. 1240.8(d).