Use ns_storage_conf:this_node_memory_data for heartbeats.
Use ns_storage_conf:this_node_memory_data for heartbeats.

This allows experimenting with memory quota validation code by setting
MEMBASE_RAM_MEGS env variable.

Change-Id: I941c91d670c654b6d627760246573b5376852a3e
Reviewed-on: http://review.couchbase.org/54030
Reviewed-by: Poonam D <6855f09986fe28ed7e8cdd9d60db878d898703d5@couchbase.com>
Tested-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

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