MB-15303: Gather only ops and ep_bg_fetched for cluster overview.
MB-15303: Gather only ops and ep_bg_fetched for cluster overview.

Change-Id: I463e7af651ff779913de6dd9be30e265634815e3
Reviewed-on: http://review.couchbase.org/53769
Tested-by: Poonam D <6855f09986fe28ed7e8cdd9d60db878d898703d5@couchbase.com>
Reviewed-by: Artem Stemkovski <15a0730a27c69f62ab86f2b6c639fca202166c02@couchbase.com>

membase/ns_server,membase/ns_server,ceejatec/ns_server,ceejatec/ns_server,membase/ns_server,ceejatec/ns_server,ceejatec/ns_server,ceejatec/ns_server,membase/ns_server,membase/ns_server,membase/ns_server,ceejatec/ns_server