Update the list of collected memcached stats.
Update the list of collected memcached stats.

Added almost all non-raw stats that cbstats provides. Notably, failover
logs were nowhere to be found.

Change-Id: I63d0b40639fc00ac6f040065e786f06dd91e4248
Reviewed-on: http://review.couchbase.org/55510
Tested-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>
Reviewed-by: Artem Stemkovski <15a0730a27c69f62ab86f2b6c639fca202166c02@couchbase.com>

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