fixed 删除用户时issue，pr用户显示已注销

app/views/api/v1/issues/journals/_detail.json.jbuilder

@@ -2,12 +2,8 @@ json.id journal.id
 json.is_journal_detail journal.is_journal_detail? 
 json.created_at journal.created_on.strftime("%Y-%m-%d %H:%M")
 json.updated_at journal.updated_on.strftime("%Y-%m-%d %H:%M")
-json.user do 
-  if journal.user.present? 
-    json.partial! "api/v1/users/simple_user", user: journal.user
-  else 
-    json.nil! 
-  end
+json.user do
+  json.partial! "api/v1/users/simple_user", user: journal.user
 end
 if journal.is_journal_detail? 
   detail = journal.journal_details.take