policy: enable full-rbf by default

Enable full rbf (mempool policy) by default and update tests accordingly.

test/functional/p2p_permissions.py

@@ -119,6 +119,9 @@ class P2PPermissionsTests(BitcoinTestFramework):
 
         self.log.debug("Check that node[1] will not send an invalid tx to node[0]")
         tx.vout[0].nValue += 1
+        # add dust to cause policy rejection but no disconnection
+        tx.vout.append(tx.vout[0])
+        tx.vout[-1].nValue = 0
         txid = tx.rehash()
         # Send the transaction twice. The first time, it'll be rejected by ATMP because it conflicts
         # with a mempool transaction. The second time, it'll be in the m_recent_rejects filter.
@@ -126,7 +129,7 @@ class P2PPermissionsTests(BitcoinTestFramework):
             [tx],
             self.nodes[1],
             success=False,
-            reject_reason='{} (wtxid={}) from peer=0 was not accepted: txn-mempool-conflict'.format(txid, tx.getwtxid())
+            reject_reason='{} (wtxid={}) from peer=0 was not accepted: dust'.format(txid, tx.getwtxid())
         )
 
         p2p_rebroadcast_wallet.send_txs_and_test(