MB-13627 Revert "disable index stats gathering by default"
MB-13627 Revert "disable index stats gathering by default"

This reverts commit 6086243fee2556ab5a7ac7f8b35687236bf67e5f.

Change-Id: Iaff2b6a457a5de68a6fcd87716adf37228ad6f56
Reviewed-on: http://review.couchbase.org/47474
Tested-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>
Reviewed-by: Dave Finlay <7b10a9ed9f70e64c30b07607a671ae61c33f14c8@couchbase.com>

ceejatec/ns_server,nimishzynga/ns_server,mschoch/ns_server,nimishzynga/ns_server,mschoch/ns_server,ceejatec/ns_server,ceejatec/ns_server,mschoch/ns_server,nimishzynga/ns_server,membase/ns_server,ceejatec/ns_server,nimishzynga/ns_server,mschoch/ns_server,nimishzynga/ns_server,membase/ns_server,membase/ns_server,ceejatec/ns_server,mschoch/ns_server,ceejatec/ns_server,membase/ns_server,membase/ns_server,nimishzynga/ns_server,membase/ns_server,mschoch/ns_server