Can't determine viewability without enable_share

[perrygeo]

The features views rely on a helper function (get_object_for_viewing or _editing) to determine permissions and respond accordingly. If enable_share() has not been run, the permission does not exist and the view errors out.

The desired behavior would be to simply say "No the object isn't shared with you" - whether that goes in the helper function or something else like a permissions fixture is TBD.