Philippe Vaucher reported this typo

 curl_easy_perform(easyhandle); /* post away! */

 curl_formfree(post); /* free post */

 curl_slist_free_all(post); /* free custom header list */

 curl_slist_free_all(headers); /* free custom header list */

.fi

Since all options on an easyhandle are "sticky", they remain the same until