message: Remove unnecessary HumanAddr in test code
diff: @@ -675,7 +675,7 @@ mod tests {
  let mut deps = mock_dependencies(&[]);
  set_validator(&mut deps.querier);
  - let creator = HumanAddr::from("creator");
  + let creator = String::from("creator");
  let instantiate_msg = default_init(2, 50);
  let info = mock_info(&creator, &[]);
  @@ -684,7 +684,7 @@ mod tests {
  assert_eq!(0, res.messages.len());
  // let's bond some tokens now
  - let bob = HumanAddr::from("bob");
  + let bob = String::from("bob");
  let bond_msg = ExecuteMsg::Bond {};
  let info = mock_info(&bob, &[coin(500, "photon")]);
  