For rendering partials that are views associated with the controller (e.g. for users controller, they reside in view/katello/users), the namespace should not be needed.

For example, following should be ok, since view/katello/users/_edit.html.haml exists:
render :partial => "edit"

but, since the _list_item.html.haml does not exist in views/katello/users, it must be namespaced:
render :partial => "katello/common/list_item"