fix build and socket_io test

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@9934 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
factor out error handling in lazy_bdecode

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@9935 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda