ISPN-4112 RHQ library plugin: restart cache -- availability report DOWN

but cache running

* Added back in availibilty down for cache not running
* Added server changes to also report DOWN when cache not running

https://issues.jboss.org/browse/ISPN-4112
Yeah I was debating about that, I didn't know if keeping the extra collection around all the time was worth it for this or not.  But I can add it in.