improve DHT logging a bit

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@10346 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
remove pointless DHT extension (for IPv6)

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@10347 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
merged changes from RC_1_0

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@10350 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda