HTTP: stored matched action in nxt_http_request_t.

No functional changes.

src/nxt_http_static.c

@@ -696,6 +696,8 @@ nxt_http_static_next(nxt_task_t *task, nxt_http_request_t *r,
         if (nxt_slow_path(r->log_route)) {
             nxt_log(task, NXT_LOG_NOTICE, "\"fallback\" taken");
         }
+
+        r->action = action->fallback;
         nxt_http_request_action(task, r, action->fallback);
         return;
     }