MB-11939: corrected typos

Change-Id: I8c88e1a2bd7336160867dd3c278d59283886c7cb
Reviewed-on: http://review.couchbase.org/41358
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>