re-introduce check for receiving duplicate data packets. Don't store data packets we have already received and acked
re-introduce check for receiving duplicate data packets. Don't store data packets we have already received and acked

git-svn-id: c33880c105b4082c86d872cc05f56ac71c9e5733@4544 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda

steeve/libtorrent,steeve/libtorrent,steeve/libtorrent,steeve/libtorrent,steeve/libtorrent,steeve/libtorrent