message: if we have to use the fallback fee rate, log the error that caused us to do so
  Summary: this would have helped us debug a client issue recently
  Reviewers: alex, arik, benchan
  Subscribers: ben
diff: @@ -239,6 +239,7 @@ exports.createTransaction = function(params) {
  else {
  // couldn't estimate the fee, proceed using the default
  feeRate = constants.fallbackFeeRate;
  + console.log("Error estimating fee for send from " + params.wallet + ": " + e.message);
  return Q();
  }
  });
  