dropbear: fix wtmp support by partially reverting [https://github.com/mkj/dropbear/commit/e5c52796c3ba722fae28f95258ad3dfcb7b31be3 this] git commit


git-svn-id: file:///var/svn/freetz/trunk@12303 149334a1-2f27-0410-a3b9-fc62619ac1e6