certificates: use the correct openssl (libressl) binary

src/www/system_certmanager.php

@@ -212,7 +212,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
     } elseif ($act == "info") {
       if (isset($id)) {
           // use openssl to dump cert in readable format
-          $process = proc_open('/usr/bin/openssl x509 -text', array(array("pipe", "r"), array("pipe", "w")), $pipes);
+          $process = proc_open('/usr/local/bin/openssl x509 -text', array(array("pipe", "r"), array("pipe", "w")), $pipes);
           if (is_resource($process)) {
              fwrite($pipes[0], base64_decode($a_cert[$id]['crt']));
              fclose($pipes[0]);