Show short scriptPubKeys correctly

Previously bitcoin-qt's -debug transaction info was showing CTxOut([error])

It is valid for a scriptPubKey to be any size, for example simply
OP_RETURN is valid and can be used to destroy a TXOUT to mining fees.

src/core.cpp

@@ -63,8 +63,6 @@ uint256 CTxOut::GetHash() const
 
 std::string CTxOut::ToString() const
 {
-    if (scriptPubKey.size() < 6)
-        return "CTxOut(error)";
     return strprintf("CTxOut(nValue=%"PRI64d".%08"PRI64d", scriptPubKey=%s)", nValue / COIN, nValue % COIN, scriptPubKey.ToString().substr(0,30).c_str());
 }