Feature #272 - Avoiding direct use of the function mb_convert_encoding(), replacing with api_convert_encoding().

main/admin/sub_language_ajax.inc.php

@@ -22,7 +22,7 @@ if (isset($new_language) && isset($language_variable) && isset($file_id)) {
 	SubLanguageManager::add_file_in_language_directory ($dokeos_path_folder);
 
 	//update variable language
-	$all_file_of_directory[$language_variable]="\"".mb_convert_encoding($new_language,$charset,'UTF-8')."\";";
+	$all_file_of_directory[$language_variable]="\"".api_convert_encoding($new_language,$charset,'UTF-8')."\";";
 
 	foreach ($all_file_of_directory as $key_value=>$value_info) {
 		SubLanguageManager::write_data_in_file ($dokeos_path_folder,$value_info,$key_value);