Recover open ledger transactions to the queue (RIPD-1530):

* If the transaction can't be queued, recover to the open ledger once,
  and drop it on the next attempt.
* New result codes for transactions that can not queue.
* Add minimum queue size.
* Remove the obsolete and incorrect SF_RETRY flag.
* fix #2215

src/ripple/overlay/impl/PeerImp.cpp

@@ -1056,6 +1056,8 @@ PeerImp::onMessage (std::shared_ptr <protocol::TMTransaction> const& m)
     {
         // If we've never been in synch, there's nothing we can do
         // with a transaction
+        JLOG(p_journal_.debug()) << "Ignoring incoming transaction: " <<
+            "Need network ledger";
         return;
     }
 
@@ -1075,11 +1077,10 @@ PeerImp::onMessage (std::shared_ptr <protocol::TMTransaction> const& m)
             if (flags & SF_BAD)
             {
                 fee_ = Resource::feeInvalidSignature;
+                JLOG(p_journal_.debug()) << "Ignoring known bad tx " <<
+                    txID;
                 return;
             }
-
-            if (!(flags & SF_RETRY))
-                return;
         }
 
         JLOG(p_journal_.debug()) << "Got tx " << txID;