fix sahara service-type

the sahara service-type is data-processing,not data_processing
if use data_processing,the sahara client will take mistake.
refer to [1]

[1] https://docs.openstack.org/sahara/latest/install/installation-guide.html#common-installation-steps


Co-Authored-By: zhulingjie <easyzlj@gmail.com>

Change-Id: I4c6704a81921bf713073451dc4e93e44234e5a7c

ansible/roles/sahara/tasks/register.yml

@@ -4,7 +4,7 @@
     module_name: "kolla_keystone_service"
     module_args:
       service_name: "sahara"
-      service_type: "data_processing"
+      service_type: "data-processing"
       description: "Sahara Data Processing"
       endpoint_region: "{{ openstack_region_name }}"
       url: "{{ item.url }}"