bug #385 compatibility with PHP7

* replace old-style constructor with PHP5-style constructor (__construct)
* do not call set_magic_quotes_runtime() any longer
* avoid automatic conversion from array to string

admin/include/functions_upgrade.php

@@ -174,10 +174,7 @@ UPDATE '.PREFIX_TABLE.'user_infos
 // Deactivate all templates
 function deactivate_templates()
 {
-  $query = '
-  UPDATE '.PREFIX_TABLE.'config
-    SET value = \''. array() .'\'
-  WHERE param = \'extents_for_templates\';';
+  conf_update_param('extents_for_templates', array());
 }
 
 // Check access rights
@@ -322,4 +319,4 @@ function upgrade_db_connect()
     my_error(l10n($e->getMessage()), true); 
   }
 }
-?>
+?>