message: Do not relay transactions if the bloom filter is empty
  When an SPV peer sends us a filterload we were automatically turning
  on fRelayTxes=true however if they send us an empty filter we were
  ending up sending them all INV's whereas really we should not be sending
  them any.
diff: @@ -1859,13 +1859,14 @@ bool ProcessMessage(CNode *pfrom, std::string strCommand, CDataStream &vRecv, in
  dosMan.Misbehaving(pfrom, 100);
  return false;
  }
  - else
  - {
  +
  LOCK(pfrom->cs_filter);
  delete pfrom->pfilter;
  pfrom->pfilter = new CBloomFilter(filter);
  - }
  + if (!pfrom->pfilter->IsEmpty())
  pfrom->fRelayTxes = true;
  + else
  + pfrom->fRelayTxes = false;
  }
  