If xwiki.unknownActionResponse=view and users view a page which doesn't exist with unknown action, they get an empty page instead of "not found".

Test case:
open xwiki.cfg and set
xwiki.unknownActionResponse=view

open /xwiki/bin/Some/NonexistantPage
observe an empty page instead of the desired page not found error.

The problem is UnknownAction.render returns "view" but doesn't set the action in the context to view and the page nonexistant message depends on the action in the context being view.