When saintmode_threshold items have been added to the trouble-list, the
backend will be considerd sick until one has timed out. Setting the
threshold to 0 disables saintmode and any lock contention associated with
it.

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@4328 d4fa192b-c00b-0410-8231-f00ffab90ce4