Notice: Undefined index: localized_options in menu_navigation_links() on file/% subpages

When visiting a page like file/21/edit, the error "Notice: Undefined index: localized_options in menu_navigation_links()" appears.

Results from this bug: #1018614: Inaccessible menu items in navigation links cause "Notice: Undefined index: localized_options".

Specifically:

• file_entity declares the menu item 'file/%file', which is saved as 'file/%'.
• In debut_media we provide a page view at 'file' and add it to the main menu.
• When at a sub-item of file/%, the secondary menu generation hits the bug described in #1018614 because the file/% item cannot be accessed and so hasn't been localized.