core: allow route(...) usage inside onsend_route block

- GH #4130

(cherry picked from commit 6343713bcc91a499c772fc6f548597693f220c35)

src/core/cfg.y

@@ -2886,6 +2886,7 @@ fcmd:
 				case MODULE5_T:
 				case MODULE6_T:
 				case MODULEX_T:
+				case ROUTE_T:
 				case SET_FWD_NO_CONNECT_T:
 				case SET_RPL_NO_CONNECT_T:
 				case SET_FWD_CLOSE_T: