ratelimit should not be enabled in nolimit pipeline
ratelimit should not be enabled in nolimit pipeline

This change fixes the wrong instruction in admin guide which enables
ratelimit in the keystone_nolimit pipeline. To use a pipeline with
ratelimit, [DEFAULT] api_rate_limit should be set to True.

Change-Id: I0cfde1c5a18eeb6ace5bc96e728e58954d0ac046

openstack/manila,openstack/manila