优化删除聊天记录逻辑

app/enterprise/controller/Im.php

@@ -451,7 +451,7 @@ class Im extends BaseController
                 }
             } else {
                 if ($message['del_user'] > 0) {
-                    $message->where($map)->delete();
+                    $message->delete();
                     return success(lang('system.delOk'));
                 }
             }