修复账单如果没有附件则现实错误页面的问题

application/em/model/EmInvoice.php

@@ -125,6 +125,7 @@ class EmInvoice extends Base
                 if($receipt) $useage['photo'] = $receipt;
             }
         } else {
+            $useage = $uModel;
             $useage['photo'] = [];
         }