-fix build order

git-svn-id: https://gnunet.org/svn/gnunet@33595 140774ce-b5e7-0310-ab8b-a85725594a96
-fix leak

git-svn-id: https://gnunet.org/svn/gnunet@33596 140774ce-b5e7-0310-ab8b-a85725594a96
-check return value, doxygen

git-svn-id: https://gnunet.org/svn/gnunet@33597 140774ce-b5e7-0310-ab8b-a85725594a96