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

- GH #4130

(cherry picked from commit 6343713bcc91a499c772fc6f548597693f220c35)
(cherry picked from commit 0b48c889623a19ed223c252ada049cabebee45f2)
(cherry picked from commit 7335ac5b8d174a14a4481215cc787e7cb5cd4542)

src/core/cfg.y

@@ -2766,6 +2766,7 @@ 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: