VOL-1431, SEBA-436 Add DHCP responder

Change-Id: Ifdc614a8b5a212e23308d4fcc71987b75397fea2
diff --git a/core/openolt_service.go b/core/openolt_service.go
index 364d0c3..4b13f3e 100644
--- a/core/openolt_service.go
+++ b/core/openolt_service.go
@@ -17,12 +17,11 @@
 package core
 
 import (
-	"time"
-
 	"gerrit.opencord.org/voltha-bbsim/common/logger"
 	"gerrit.opencord.org/voltha-bbsim/common/utils"
 	"gerrit.opencord.org/voltha-bbsim/device"
 	"gerrit.opencord.org/voltha-bbsim/protos"
+	"time"
 )
 
 func sendOltIndUp(stream openolt.Openolt_EnableIndicationServer, olt *device.Olt) error {