better logging of needed angeltypes for shifts and rooms

includes/controller/shifts_controller.php

@@ -149,8 +149,10 @@ function shift_edit_controller()
             $needed_angel_types_info = [];
             foreach ($needed_angel_types as $type_id => $count) {
                 NeededAngelType_add($shift_id, $type_id, null, $count);
+                if($count > 0) {
                     $needed_angel_types_info[] = $angeltypes[$type_id] . ': ' . $count;
                 }
+            }
 
             engelsystem_log(
                 'Updated shift \'' . $shifttypes[$shifttype_id] . ', ' . $title