[VOL-3184] Core panic fix in debug mode

Change-Id: I3d28fe0507c766dd394570ff9c02acd3aa7dce85
diff --git a/rw_core/route/device_route.go b/rw_core/route/device_route.go
index 71002c7..3cb8470 100644
--- a/rw_core/route/device_route.go
+++ b/rw_core/route/device_route.go
@@ -330,6 +330,8 @@
 
 // Print prints routes
 func (dr *DeviceRoutes) Print() error {
+	dr.routeBuildLock.RLock()
+	defer dr.routeBuildLock.RUnlock()
 	logger.Debugw("Print", log.Fields{"logical-device-id": dr.logicalDeviceID, "logical-ports": dr.logicalPorts})
 	if logger.V(log.DebugLevel) {
 		output := ""