CBQE-1760: fix cli help

Change-Id: I1750bd369409977a2444381e38f177ff247cd933
Reviewed-on: http://review.couchbase.org/31035
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>