re-queue on error sending

[st0ff3r]

esp_mqtt/mqtt/mqtt.c

Line 757 in 37cab7c

espconn_send(client->pCon, dataBuffer, dataLen);

should be replaced with
if (espconn_send(client->pCon, dataBuffer, dataLen) != 0) {
// error sending, put it back into the queue again
if (QUEUE_Puts(&client->msgQueue, dataBuffer, dataLen) == -1) {
INFO("MQTT: Queue full\r\n");
}
}

and same in line 751