Fixing memory leak reported by valgrind

==33104==    by 0x10009D20C: std::map<CNetAddr, int, std::less<CNetAddr>, std::allocator<std::pair<CNetAddr const, int> > >::erase(CNetAddr const&) (stl_map.h:469)
==33104==    by 0x100095D9E: CAddrMan::ShrinkNew(int) (addrman.cpp:166)
More updates on the I2P seed process