- store own hello

git-svn-id: https://gnunet.org/svn/gnunet@32221 140774ce-b5e7-0310-ab8b-a85725594a96
- simplify timing out of old hellos

git-svn-id: https://gnunet.org/svn/gnunet@32222 140774ce-b5e7-0310-ab8b-a85725594a96
- ignore NULL hellos

git-svn-id: https://gnunet.org/svn/gnunet@32223 140774ce-b5e7-0310-ab8b-a85725594a96
- don't call set on NULL hellos

git-svn-id: https://gnunet.org/svn/gnunet@32224 140774ce-b5e7-0310-ab8b-a85725594a96