warden: Make SSH detection more robust
warden: Make SSH detection more robust

After enabling rsyslog upstart appeared to stop emitting the "running"
event for SSH. Instead, grep for every target state and see if "spawned"
is one of them.

Change-Id: I4535e7ef24d2eb67e17e50f3df7ef7b512814476

cloudfoundry-incubator/garden-linux,tsaleh/garden,cloudfoundry-incubator/garden,cloudfoundry-incubator/garden-linux,cloudfoundry-incubator/garden-linux,savaki/garden,savaki/garden,shashidharatd/garden-linux,shashidharatd/garden-linux,tangfeixiong/garden,tsaleh/garden,tangfeixiong/garden,shashidharatd/garden-linux,shashidharatd/garden-linux,cloudfoundry-incubator/garden