Reduce another spammy error to debug
Reduce another spammy error to debug

This one is triggered when the proxy fails because the remote refuses
the connection, which is another example of not-an-error from our point
of view.

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@docker.com>

djs55/vpnkit,djs55/vpnkit,djs55/vpnkit