fixed extended handshake error handling to be more robust and fix extension message precedence over plugins
fixed extended handshake error handling to be more robust and fix extension message precedence over plugins

git-svn-id: 6ed3528c1be4534134272ad6dd050eeaa1f628d3@5291 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda

svn2github/libtorrent-trunk,svn2github/libtorrent-trunk,svn2github/libtorrent-trunk,svn2github/libtorrent-trunk