Update v3 oauth consumers tests to work w/ pre-prov

I don't see any limitations by using pre-provisioned
credentials for these tests:

* test_create_and_show_consumer
* test_delete_consumer
* test_update_consumer
* test_list_consumers

Change-Id: Id83ed377a0259bf5001674b286e5ec4623bcfbe4
diff --git a/tempest/api/identity/admin/v3/test_oauth_consumers.py b/tempest/api/identity/admin/v3/test_oauth_consumers.py
index 062cce5..7a85f84 100644
--- a/tempest/api/identity/admin/v3/test_oauth_consumers.py
+++ b/tempest/api/identity/admin/v3/test_oauth_consumers.py
@@ -21,6 +21,10 @@
 
 
 class OAUTHConsumersV3Test(base.BaseIdentityV3AdminTest):
+    # NOTE: force_tenant_isolation is true in the base class by default but
+    # overridden to false here to allow test execution for clouds using the
+    # pre-provisioned credentials provider.
+    force_tenant_isolation = False
 
     def _create_consumer(self):
         """Creates a consumer with a random description."""