Initialize `arg_str1'.


git-svn-id: https://gnunet.org/svn/gnunet@33622 140774ce-b5e7-0310-ab8b-a85725594a96
fixing compile error


git-svn-id: https://gnunet.org/svn/gnunet@33623 140774ce-b5e7-0310-ab8b-a85725594a96