delete node from HA stack when deleted from cluster

delete node from HA stack when deleted from cluster

When a node gets deleted from the cluster with pvecm delnode
we set it's node state in the manager status to 'gone'.
When set to gone the manager waits an hour after the node was last
seen online and only then deletes it from the manager status.

When some HA services were forgotten on the node (shouldn't happen
at all!!) the node will be fenced, the service migrated and then its
state reset to 'gone'. After an hour the node will be deleted,
unless it joined the cluster again in the meantime.

Deleting a node from the HA manager status is by no means a final
act, the ha-manager could live without deleting it, but for the user
it is confusing to see dead nodes in the interface.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>