make subversion build system detect that serf, which is really available
   and working, is available and working
 - remove ssl, as there is nothing to do with ssl on subversion
 - add gentoo patch which removes a lot of automatically detected garbage from
   subversion build system


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@40471 20353a03-c40f-0410-a6d1-a30d3c3de9de