fix doxygen errors in comments


git-svn-id: https://gnunet.org/svn/gnunet@31398 140774ce-b5e7-0310-ab8b-a85725594a96
- signal shutdown, don't create new connections, fix 3214


git-svn-id: https://gnunet.org/svn/gnunet@31399 140774ce-b5e7-0310-ab8b-a85725594a96
- not an error, always happens on relay nodes


git-svn-id: https://gnunet.org/svn/gnunet@31400 140774ce-b5e7-0310-ab8b-a85725594a96