This moves to update the host used for the ceph health checks, as
we should be checking the ceph-mgr service directly for ceph
metrics instead of trying to curl the host directly.
This also changes the ceph_health_check to use the base-os
hostgroup instead of the placeholder ceph-mgr host group, as we're
just executing a simple check against the ceph-mgr service.
This also adds default configuration values for the
max_concurrent_checks (60) and check_workers (4) values instead
of leaving them at the defaults Nagios uses (0 and # cores,
respectively)
Change-Id: Ib4072fcd545d8c05d5e9e4a93085a8330be6dfe0
dfb4654fba