fixup! transport: add the WolfCertTransport vtable and WOLFCERT_ERR_CONN_CLOSED

Author: yosuke-wolfssl

src/http.c

@@ -1164,13 +1164,13 @@ static int http_read_response(WolfCertConn* c,
 
 int wolfcert_http_request(const WolfCertHttpRequest* req, WolfCertHttpResponse* resp)
 {
-    if (req != NULL && req->connect_cb != NULL && req->transport != NULL)
-        return WOLFCERT_ERR(WOLFCERT_ERR_BAD_ARG, "http",
-            "set either connect_cb or transport, not both");
-
     if (req == NULL || resp == NULL || req->url == NULL || req->method == NULL)
         return WOLFCERT_ERR_BAD_ARG;
 
+    if (req->connect_cb != NULL && req->transport != NULL)
+        return WOLFCERT_ERR(WOLFCERT_ERR_BAD_ARG, "http",
+            "set either connect_cb or transport, not both");
+
     memset(resp, 0, sizeof(*resp));
     void* heap = req->heap ? req->heap : wolfcert_default_heap();
     resp->heap = heap;