Now that the VRF failures are supposed to have gone away, _do_ crash if we hit one

Still log it, though

simulator.py

@@ -139,7 +139,7 @@ class Simulator:
                     random.choice(self.clients).channelmgr.new_circuit())
             except ValueError as e:
                 self.statslogger.error(str(e))
-                next
+                raise e
 
             simtime += random.expovariate(self.gamma * numclients)
             numcircs += 1