attach_media should be in transaction of creation status (#2426)

app/services/post_status_service.rb

@@ -20,6 +20,8 @@ class PostStatusService < BaseService
     end
 
     media  = validate_media!(options[:media_ids])
+    status = nil
+    ApplicationRecord.transaction do
       status = account.statuses.create!(text: text,
                                         thread: in_reply_to,
                                         sensitive: options[:sensitive],
@@ -27,8 +29,8 @@ class PostStatusService < BaseService
                                         visibility: options[:visibility],
                                         language: detect_language_for(text, account),
                                         application: options[:application])
-
       attach_media(status, media)
+    end
     process_mentions_service.call(status)
     process_hashtags_service.call(status)