MB-14104: fix typo on help text
MB-14104: fix typo on help text

Change-Id: I3dd38f001cbce147490c398526169b6716c2f890
Reviewed-on: http://review.couchbase.org/48827
Reviewed-by: Bin Cui <ed18693fff32c00e22495f4877a3b901bed09041@gmail.com>
Tested-by: Bin Cui <ed18693fff32c00e22495f4877a3b901bed09041@gmail.com>

couchbase/couchbase-cli,couchbase/couchbase-cli