firewall: adopt formatting of RFC 1918 and IANA rules

Adopt style of RFC 1918 rule and reserved IANA rule to match user created
rules in style.

(cherry picked from commit 3dd79c51)

src/www/firewall_rules.php

@@ -319,14 +319,14 @@ $( document ).ready(function() {
               if (isset($config['interfaces'][$selected_if]['blockbogons'])): ?>
                   <tr valign="top" id="frrfc1918">
                     <td>&nbsp;</td>
-                    <td align="center"><span class="glyphicon glyphicon-remove text-danger"></span></td>
+                    <td><span class="glyphicon glyphicon-remove text-danger"></span></td>
                     <td>*</td>
                     <td><?=gettext("Reserved/not assigned by IANA");?></td>
                     <td class="hidden-xs hidden-sm">*</td>
                     <td class="hidden-xs hidden-sm">*</td>
                     <td class="hidden-xs hidden-sm">*</td>
                     <td class="hidden-xs hidden-sm">*</td>
-                    <td class="hidden-xs hidden-sm">*</td>
+                    <td class="hidden-xs hidden-sm">&nbsp;</td>
                     <td><?=gettext("Block bogon networks");?></td>
                     <td>
                       <a href="interfaces.php?if=<?=htmlspecialchars($if)?>#rfc1918" title="<?=gettext("edit rule");?>" class="btn btn-default btn-xs"><span class="glyphicon glyphicon-pencil"></span></a>