Delete pkt-out kafka topic at init

Change-Id: Ifc5272a2ce5760eeab3d62d4b273794404b2e05e
diff --git a/voltha/adapters/openolt/openolt_device.py b/voltha/adapters/openolt/openolt_device.py
index 0fb5353..4200428 100644
--- a/voltha/adapters/openolt/openolt_device.py
+++ b/voltha/adapters/openolt/openolt_device.py
@@ -14,7 +14,6 @@
 # limitations under the License.
 #
 import binascii
-import grpc
 import structlog
 import time
 from scapy.layers.l2 import Ether, Dot1Q
@@ -107,7 +106,7 @@
         self.device_info = None
 
         self._kadmin = KAdmin()
-        self._kadmin.delete_topics(['openolt.ind'])
+        self._kadmin.delete_topics(['openolt.ind', 'voltha.pktout'])
         self._grpc = None
         self.go_state_init()