Skip test tokens

This patchset skips test_token test due to the change of 401 response
for an invalid token to a 404 response.  Keystone bug 1221889.

Once the change to keystone has been accepted, a subsequent patchset
will be proposed to tempest to renable the check and accept the new
404 HTTP status for the get_token call on invalid tokens.

related-bug: 1221889
Change-Id: I3c5691f5085e10e28b0f57505133ae3478167396
diff --git a/tempest/api/identity/admin/v3/test_tokens.py b/tempest/api/identity/admin/v3/test_tokens.py
index 2a20493..4c995d3 100644
--- a/tempest/api/identity/admin/v3/test_tokens.py
+++ b/tempest/api/identity/admin/v3/test_tokens.py
@@ -19,11 +19,13 @@
 from tempest.common.utils.data_utils import rand_name
 from tempest import exceptions
 from tempest.test import attr
+import testtools
 
 
 class UsersTestJSON(base.BaseIdentityAdminTest):
     _interface = 'json'
 
+    @testtools.skip("Skipped until the Bug #1221889 is resolved")
     @attr(type='smoke')
     def test_tokens(self):
         # Valid user's token is authenticated