Correct delivered_amount reporting for minor ledgers (RIPD-1051)

The existing delivered_amount logic will erroneously report
unavailable for ledgers that aren't in the network's live
chain because it is based solely on ledger sequence number.
This adds a check based on the ledger close time to permit
the code to give correct results in standalone mode and on
test networks.

src/ripple/rpc/impl/Utilities.cpp

@@ -18,6 +18,7 @@
 //==============================================================================
 
 #include <ripple/rpc/impl/Utilities.h>
+#include <ripple/app/ledger/LedgerMaster.h>
 #include <ripple/app/misc/Transaction.h>
 #include <ripple/json/json_value.h>
 #include <ripple/protocol/JsonFields.h>
@@ -65,6 +66,19 @@ addPaymentDeliveredAmount (
         return;
     }
 
+    // If the ledger closed long after the DeliveredAmount code was deployed
+    // then its absence indicates that the amount delivered is listed in the
+    // Amount field. DeliveredAmount went live January 24, 2014.
+    auto ct =
+        context.ledgerMaster.getCloseTimeBySeq (transaction->getLedger ());
+    if (ct && (*ct > 446000000))
+    {
+        // 446000000 is in Feb 2014, well after DeliveredAmount went live
+        meta[jss::delivered_amount] =
+            serializedTx->getFieldAmount (sfAmount).getJson (1);
+        return;
+    }
+
     // Otherwise we report "unavailable" which cannot be parsed into a
     // sensible amount.
     meta[jss::delivered_amount] = Json::Value ("unavailable");