message: tell which did already exists
diff: @@ -216,7 +216,7 @@ impl DidCommandExecutor {
  if let Some(ref did) = my_did_info.did.as_ref() {
  if self.wallet_service.record_exists::<Did>(wallet_handle, did)? {
  - return Err(IndyError::DidError(DidError::AlreadyExistsError(format!("Did already exists"))));
  + return Err(IndyError::DidError(DidError::AlreadyExistsError(did.to_string())));
  };
  }
  