`password` is not required for updating a user

This patch fixes the nits from the below commit:

https://review.openstack.org/#/c/342089/

Change-Id: I062979ccce393e74e72c3d812657123151e476fd

api-ref/source/v3/parameters.yaml

@@ -1663,6 +1663,12 @@ user_tree_dn_1:
   in: body
   required: false
   type: string
+user_update_password_body:
+  description: |
+    The new password for the user.
+  in: body
+  required: false
+  type: string
 users:
   description: |
     A ``users`` object.

api-ref/source/v3/samples/admin/user-projects-list-response.json

@@ -8,8 +8,8 @@
             "links": {
                 "self": "http://example.com/identity/v3/projects/456788"
             },
-            "name": "a project name"
-            "parent_id": "212223",
+            "name": "a project name",
+            "parent_id": "212223"
         },
         {
             "description": "description of this project",
@@ -19,8 +19,8 @@
             "links": {
                 "self": "http://example.com/identity/v3/projects/456789"
             },
-            "name": "another domain"
-            "parent_id": "212223",
+            "name": "another domain",
+            "parent_id": "212223"
         }
     ],
     "links": {

api-ref/source/v3/users.inc

@@ -79,7 +79,7 @@ Request
    - domain_id: user_domain_id_update_body
    - enabled: enabled_user_update_body
    - name: user_name_update_body
-   - password: user_password_update_body
+   - password: user_update_password_body
 
 Request Example
 ---------------