When DCist left the 9:30 Club last night, a homeless man on U Street told us to smile. That might best describe our experience with seeing The Libertines live. We expected a lot more, and in the end were disappointed, realizing that a band with such great potential had floundered and came up short. (Perhaps it was the co-mingling of Jamesons and Stella Artois that was shared on stage … or was the Jamesons actually…