Related Branches Visible to Guests in Issue Activity

See merge request gitlab/gitlabhq!3537

Fix invalid byte sequence

See merge request gitlab/gitlabhq!3545

Check permissions before showing a forked project's source

See merge request gitlab/gitlabhq!3554

Ensure attributes that end in `_ids` are cleaned

See merge request gitlab/gitlabhq!3561

[ci skip]

This prevents an issue where you can steal other projects objects by
asking for ids that don't belong to you in import.

[ci skip]