MB-9635 use ISO 8601 format for timestamp in audit messages
MB-9635 use ISO 8601 format for timestamp in audit messages

... in compliance with the latest audit spec

Change-Id: Id05e4d9abf6271a79bef359c908d0d58360e51f1
Reviewed-on: http://review.couchbase.org/45405
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

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