Better function to clean generated logins

htdocs/contact/fiche.php

@@ -757,13 +757,10 @@ else
 
 		if ($_GET["action"] == 'create_user')
 		{
-			//$login=strtolower(substr(dol_string_unaccent($object->prenom), 0, 4)) . strtolower(substr(dol_string_unaccent($object->nom), 0, 4));
-			
 			// Full firstname and name separated with a dot : firstname.name 
 			// TODO add function
 			$login=strtolower(dol_string_unaccent($object->prenom)) .'.'. strtolower(dol_string_unaccent($object->nom));
-			$login=str_replace(' ','.',$login); // For particle names
-        	$login=str_replace('\'','',$login); // For simple quote
+			$login=dol_string_nospecial($login,''); // For special names
 
 			// Create a form array
 			$formquestion=array(array('label' => $langs->trans("LoginToCreate"), 'type' => 'text', 'name' => 'login', 'value' => $login));