VOL-2518 - reconnect to voltha on disconnect

Change-Id: Ia497bb6a83312f15e54de0d7556753e1d9ef58b0
diff --git a/internal/pkg/openflow/feature.go b/internal/pkg/openflow/feature.go
index 54de0d0..f456175 100644
--- a/internal/pkg/openflow/feature.go
+++ b/internal/pkg/openflow/feature.go
@@ -32,6 +32,9 @@
 				"device-id": ofc.DeviceID,
 				"request":   js})
 	}
+	if ofc.VolthaClient == nil {
+		return NoVolthaConnectionError
+	}
 	var id = common.ID{Id: ofc.DeviceID}
 	logicalDevice, err := ofc.VolthaClient.GetLogicalDevice(context.Background(), &id)
 	reply := ofp.NewFeaturesReply()