vpn: can't have zero clients

(cherry picked from commit fc381754)

src/www/vpn_l2tp.php

@@ -267,8 +267,9 @@ include("head.inc");
                     <td>
                       <select id="n_l2tp_units" name="n_l2tp_units">
                       <?php
-                                for ($x=0; $x<255; $x++) {
-                                    if ($x == $pconfig['n_l2tp_units']) {
+                                $toselect = ($pconfig['n_l2tp_units'] > 0) ? $pconfig['n_l2tp_units'] : 16;
+                                for ($x=1; $x<255; $x++) {
+                                    if ($x == $toselect) {
                                            $SELECTED = " selected=\"selected\"";
                                     } else {
                                         $SELECTED = "";

src/www/vpn_pppoe_edit.php

@@ -325,8 +325,9 @@ legacy_html_escape_form_data($pconfig);
                     <td>
                       <select id="n_pppoe_units" name="n_pppoe_units">
 <?php
-                      for ($x=0; $x<255; $x++):?>
-                        <option value="<?=$x;?>" <?=$x == $pconfig['n_pppoe_units'] ? "selected=\"selected\"" : "" ;?>>
+                      $toselect = ($pconfig['n_pppoe_units'] > 0) ? $pconfig['n_pppoe_units'] : 16;
+                      for ($x=1; $x<255; $x++):?>
+                        <option value="<?=$x;?>" <?=$x == $toselect ? "selected=\"selected\"" : "" ;?>>
                             <?=$x;?>
 <?php
                       endfor;?>