fixed 删除用户时issue，pr用户显示已注销

app/views/api/v1/issues/_simple_detail.json.jbuilder

@@ -33,11 +33,7 @@ json.time_scale issue.time_scale
 json.child_count issue.child_count
 
 json.author do
-  if issue.user.present? 
-    json.partial! "api/v1/users/simple_user", locals: {user: issue.user}
-  else 
-    json.nil! 
-  end
+  json.partial! "api/v1/users/simple_user", locals: {user: issue.user}
 end
 json.assigners issue.show_assigners.each do |assigner| 
   json.partial! "api/v1/users/simple_user", locals: {user: assigner}

app/views/api/v1/users/_simple_user.json.jbuilder

@@ -7,4 +7,5 @@ if user.present?
 else
   json.name "已注销"
   json.login ""
+  json.image_url Rails.application.config_for(:configuration)['platform_url'] + "/" + url_to_avatar(user).to_s
 end