Fixing commit 93375d9439862db53616bb98e6d137226754616f

That change made NexusApplication ERROR > INFO level
change, but seeming it's "too much", as Restlet 1.1
is still too chatty on that level (content negotiation
and other stuff is logged), while the logs we are
interested in (badly protected resources) are
logged on WARN level.
Merge remote-tracking branch 'origin/master' into nexus-5472-proxy404