Former Weather Underground radical Kathy Boudin - who spent 22 years in prison for an armored-car robbery that killed two cops and a Brinks guard - now holds a prestigious adjunct professorship at Columbia University's School of Social Work, The Post has learned. Boudin, 69, this year won another academic laurel - being named the Sheinberg Scholar-in-Residence at NYU Law School, where last month she gave a lecture on "the politics of parole and re-entry." Boudin's bounce-back into respectability after her 2003 parole comes to light a week before the release of Robert Redford's movie "The Company You Keep,"...