self.poller not used (#759)

I do not see the need for zmq and the poller being initialized and not used.

selfdrive/controls/lib/planner.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-import zmq
 import math
 import numpy as np
 from common.params import Params
@@ -65,7 +64,6 @@ def limit_accel_in_turns(v_ego, angle_steers, a_target, CP):
 class Planner(object):
   def __init__(self, CP, fcw_enabled):
     self.CP = CP
-    self.poller = zmq.Poller()
 
     self.plan = messaging.pub_sock(service_list['plan'].port)
     self.live_longitudinal_mpc = messaging.pub_sock(service_list['liveLongitudinalMpc'].port)