rgw: fix miss handle curl error return

if meet tcp packet loss, curl return will be result=18(CURLE_PARTIAL_FILE)
and http_status=200, so sync will continue and cause content miss match.

Fixes: https://tracker.ceph.com/issues/39992

Signed-off-by: Tianshan Qu <tianshan@xsky.com>
(cherry picked from commit 9b70258)

src/rgw/rgw_http_client.cc

@@ -1141,7 +1141,8 @@ void *RGWHTTPManager::reqs_thread_entry()
 	curl_easy_getinfo(e, CURLINFO_RESPONSE_CODE, (void **)&http_status);
 
 	int status = rgw_http_error_to_errno(http_status);
-        if (result != CURLE_OK && http_status == 0) {
+        if (result != CURLE_OK && status == 0) {
+          dout(0) << "ERROR: curl error: " << curl_easy_strerror((CURLcode)result) << ", maybe network unstable" << dendl;
           status = -EAGAIN;
         }
         int id = req_data->id;