Set default minrelaytxfee to 1000 zatoshis to match upstream.

A txout will be considered dust when it has a value <546 zatoshis.
Helps to address #1719.

src/main.cpp

@@ -69,7 +69,7 @@ uint64_t nPruneTarget = 0;
 bool fAlerts = DEFAULT_ALERTS;
 
 /** Fees smaller than this (in satoshi) are considered zero fee (for relaying and mining) */
-CFeeRate minRelayTxFee = CFeeRate(5000);
+CFeeRate minRelayTxFee = CFeeRate(DEFAULT_MIN_RELAY_TX_FEE);
 
 CTxMemPool mempool(::minRelayTxFee);