message: CHANGELOG: Add ExportController HTTP 404 entries
diff: @@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
  - Chat system access denial unit tests. [#989](https://github.com/geli-lms/geli/issues/989)
  - `DuplicationController` access denial unit tests. [#1016](https://github.com/geli-lms/geli/issues/1016)
  - `ExportController` access denial unit tests. [#1039](https://github.com/geli-lms/geli/issues/1039)
  +- `ExportController` 404 unit tests. [#1039](https://github.com/geli-lms/geli/issues/1039)
  - `TestHelper` class for shared API unit test functionality. [#989](https://github.com/geli-lms/geli/issues/989) [#1016](https://github.com/geli-lms/geli/issues/1016)
  - `extractSingleMongoId` variant of the `ExtractMongoId` utility function(s). [#989](https://github.com/geli-lms/geli/issues/989)
  - Show message count for unit chat. [#933](https://github.com/geli-lms/geli/issues/993)
  @@ -39,6 +40,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
  - Nondeterministic chat system unit test authorization failures. [#989](https://github.com/geli-lms/geli/issues/989)
  - Unnecessarily verbose `DuplicationController` route responses. [#1016](https://github.com/geli-lms/geli/issues/1016)
  - Prepare mongoose update. [#1003](https://github.com/geli-lms/geli/issues/1003) [#1027](https://github.com/geli-lms/geli/pull/1027)
  +- `ExportController` missing 404 handling. [#1039](https://github.com/geli-lms/geli/issues/1039)
  ### Security
  - Fixed multiple severe security issues of the chat system. [#989](https://github.com/geli-lms/geli/issues/989)
  