兼容php5.5

@@ -59,7 +59,8 @@ class RegisterController extends WebAction
                 $data['message'] = '由于你IP受限无法注册';
                 break;
             }
-            if(!empty(PassportModel::getUserInfoByMobile($area, $mobile))) {
+            $user = PassportModel::getUserInfoByMobile($area, $mobile);
+            if(!empty($user)) {
                $data['message'] = '手机号码已经存在';
                break;
             }