Add role_domain_id_request_body in parameters

Now use domain_id_response_body in the request parameters of
creating role, but its required is true. When we create a role,
the domain id is optional.
This patch add role_domain_id_request_body in request parameters.

Change-Id: Ib384f2b074e86691223fbc3d480fbb82a903e209

api-ref/source/v3/parameters.yaml

@@ -1299,6 +1299,12 @@ role_assignments:
   in: body
   required: true
   type: array
+role_domain_id_request_body:
+  description: |
+    The ID of the domain of the role.
+  in: body
+  required: false
+  type: string
 role_id_response_body:
   description: |
     The role ID.

api-ref/source/v3/roles.inc

@@ -166,7 +166,7 @@ Request Parameters
 
    - role: role
    - name: role_name_create_body
-   - domain_id: domain_id_response_body
+   - domain_id: role_domain_id_request_body
 
 Request Example
 ---------------