fix for when lsd, upnp or nat-pmp is started more than once
fix for when lsd, upnp or nat-pmp is started more than once

git-svn-id: a9fe57c6430a6997a38eed96ede4af2f77d6b776@1755 a83610d8-ad2a-0410-a6ab-fc0612d85776

chongyc/libtorrent,chongyc/libtorrent,chongyc/libtorrent,chongyc/libtorrent