Add TheSeven's dnsseed
Add TheSeven's dnsseed

TheSeven has kindly provided an auto dns seed service for peercoin. This change adds TheSeven's dnsseed to the dnsseed list.(cherry picked from commit 6e09a5f6d36b229dcd1f4ca04ea899d97775360e)

(cherry picked from commit 650ea5f6ac14da491f0f0260e05ef07fccd53798)

FuzzyBearBTC/peercoin,FuzzyBearBTC/peercoin,slimcoin-project/Slimcoin,slimcoin-project/Slimcoin,Peerapps/ppcoin,FuzzyBearBTC/peercoin,BeirdoMud/MudCoin,slimcoin-project/Slimcoin,BeirdoMud/MudCoin,BeirdoMud/MudCoin,Peerapps/ppcoin,slimcoin-project/Slimcoin,FuzzyBearBTC/peercoin,bitgrowchain/bitgrow,Peerapps/ppcoin,bitgrowchain/bitgrow,Peerapps/ppcoin,bitgrowchain/bitgrow,bitgrowchain/bitgrow,BeirdoMud/MudCoin,slimcoin-project/Slimcoin,slimcoin-project/Slimcoin