Revert "Relay double-spends, subject to anti-DOS"

This reverts commit d640a3ceab.

src/core.cpp

@@ -124,22 +124,6 @@ CTransaction& CTransaction::operator=(const CTransaction &tx) {
     return *this;
 }
 
-bool CTransaction::IsEquivalentTo(const CTransaction& tx) const
-{
-    if (nVersion   != tx.nVersion   ||
-        nLockTime  != tx.nLockTime  ||
-        vin.size() != tx.vin.size() ||
-        vout       != tx.vout)
-        return false;
-    for (unsigned int i = 0; i < vin.size(); i++)
-    {
-        if (vin[i].nSequence != tx.vin[i].nSequence ||
-            vin[i].prevout   != tx.vin[i].prevout)
-            return false;
-    }
-    return true;
-}
-
 int64_t CTransaction::GetValueOut() const
 {
     int64_t nValueOut = 0;