plugins: follow the footsteps of plugins_syslog() and plugins_services()

This looks simple enough now.  Discussed with @adschellevis.

src/etc/inc/config.lib.inc

@@ -177,9 +177,15 @@ function write_config($desc = '', $backup = true)
         return -1;
     }
 
+    if (function_exists('plugins_interfaces')) {
+        /* only pull plugins if plugins.inc was included before */
+        plugins_interfaces(false);
+    }
+
     $cnf = OPNsense\Core\Config::getInstance();
     $cnf->fromArray($config);
     $revision_info = make_config_revision_entry($desc);
+
     try {
         $cnf->save($revision_info, $backup);
     } catch (OPNsense\Core\ConfigException $e) {

src/etc/inc/openvpn_wizard.inc

@@ -732,7 +732,6 @@ function step12_submitphpaction()
     $config['openvpn']['openvpn-server'][] = $server;
 
     openvpn_resync('server', $server);
-    plugins_interfaces(false);
     write_config();
     header("Location: vpn_openvpn_server.php");
     exit;

src/www/interfaces_groups.php

@@ -53,7 +53,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             }
         }
         unset($a_ifgroups[$id]);
-        plugins_interfaces(false);
         write_config();
         header("Location: interfaces_groups.php");
         exit;

src/www/interfaces_groups_edit.php

@@ -125,7 +125,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
           // add new item
           $a_ifgroups[] = $ifgroupentry;
       }
-      plugins_interfaces(false);
       write_config();
       interface_group_setup($ifgroupentry);
       header("Location: interfaces_groups.php");

src/www/vpn_ipsec.php

@@ -88,7 +88,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         } elseif (isset($config['ipsec']['enable'])) {
             unset($config['ipsec']['enable']);
         }
-        plugins_interfaces(false);
         write_config();
         ipsec_configure();
         filter_configure();
@@ -118,7 +117,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             unset($config['ipsec']['phase1'][$p1entrydel]);
         }
 
-        plugins_interfaces(false);
         write_config();
         mark_subsystem_dirty('ipsec');
         header("Location: vpn_ipsec.php");

src/www/vpn_ipsec_mobile.php

@@ -170,10 +170,8 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
 
             $config['ipsec']['client'] = $client;
 
-            plugins_interfaces(false);
             write_config();
             mark_subsystem_dirty('ipsec');
-
             header(url_safe('Location: vpn_ipsec_mobile.php'));
             exit;
         }

src/www/vpn_ipsec_phase1.php

@@ -387,7 +387,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
             }
         }
 
-        plugins_interfaces(false);
         write_config();
         mark_subsystem_dirty('ipsec');
         header("Location: vpn_ipsec.php");

src/www/vpn_openvpn_client.php

@@ -135,7 +135,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         if (isset($id)) {
             openvpn_delete('client', $a_client[$id]);
             unset($a_client[$id]);
-            plugins_interfaces(false);
             write_config();
         }
         header("Location: vpn_openvpn_client.php");
@@ -148,7 +147,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
                     unset($a_client[$rulei]);
                 }
             }
-            plugins_interfaces(false);
             write_config();
         }
         header("Location: vpn_openvpn_client.php");
@@ -339,7 +337,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
             }
 
             openvpn_resync('client', $client);
-            plugins_interfaces(false);
             write_config();
 
             header("Location: vpn_openvpn_client.php");

src/www/vpn_openvpn_server.php

@@ -139,7 +139,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         if (isset($a_server[$id])) {
             openvpn_delete('server', $a_server[$id]);
             unset($a_server[$id]);
-            plugins_interfaces(false);
             write_config();
         }
         header("Location: vpn_openvpn_server.php");
@@ -404,7 +403,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
             }
 
             openvpn_resync('server', $server);
-            plugins_interfaces(false);
             write_config();
             openvpn_resync_csc(); // dump client specific overrides, the required set may have changed