Fix bug 1057286: Split file attachments from wiki into a separate application.
fix bug 1057286 - fix attachments migrations' db_table value
fix bug 1057286 - make migration 0004 work for new and existing environments
Merge pull request #2732 from groovecoder/attachments-app-1057286

fix bug 1057286 - split file attachments from wiki into a separate application