correctly hide empty niql stats block
correctly hide empty niql stats block

I.e. not just after template renderings, but when we change
hidingQueryBlock variable too.

Change-Id: I1941dd4b791939e9f38424e8902f4328176a6586
Reviewed-on: http://review.couchbase.org/46004
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

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