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: 4f0141143c3c635d33f1b9f02fcb2b6c73e45c89@5291 a83610d8-ad2a-0410-a6ab-fc0612d85776

svn2github/libtorrent-rasterbar-trunk,dpolishuk/libtorrent,svn2github/libtorrent-rasterbar-trunk,svn2github/libtorrent-rasterbar-trunk,dpolishuk/libtorrent,dpolishuk/libtorrent,dpolishuk/libtorrent,svn2github/libtorrent-rasterbar-trunk,dpolishuk/libtorrent,dpolishuk/libtorrent