Fix v2-ext API enabled documentation

The 'enabled' key in the parameters list refers to a tenant, not a
user. The `/v2.0/users/{userId}/OS-KSADM/enabled` method is operating
on a user, so we should use the 'enabled_1' key. 'enabled_1' is not a
very descriptive name so let's call it 'enabled_user' instead.

Moreover, this parameter is required, so it does not make sense for it
to have a default when the user must supply a value, so this patch
modifies the 'enabled_1' (now called 'enabled_user') description to
reflect that.

Change-Id: I81a7c68d5000ca6acab74679b49eeb619a5b914e

api-ref/source/v2-ext/ksadm-admin.inc

@@ -24,7 +24,7 @@ Request
 .. rest_parameters:: parameters.yaml
 
    - userId: userId
-   - enabled: enabled
+   - enabled: enabled_user
 
 Request Example
 ---------------

api-ref/source/v2-ext/parameters.yaml

@@ -78,10 +78,10 @@ enabled:
   in: body
   required: true
   type: boolean
-enabled_1:
+enabled_user:
   description: |
-    Indicates whether the user is enabled (``true``)
-    or disabled(``false``). The default value is ``true``.
+    Indicates whether the user should be enabled (``true``)
+    or disabled(``false``).
   in: body
   required: true
   type: boolean