[api-ref] Correct parameter's type
[api-ref] Correct parameter's type

This patch corrects type of 'limit' parameter from 'type: int'
to 'type: integer'.

Change-Id: I2b7dd8efdab954f998b152d17b4c4601d8e7ad57

openstack/senlin,openstack/senlin,openstack/senlin,stackforge/senlin,stackforge/senlin