Use a valid project_id flavor_access neg tests

Based on substantial use feedback, Nova is validating the project_id
for both quotas and flavor access calls, so that when a 200 success is
returned to the user, it is because the API call actually succeeded,
not a failed call which returns success, and confuses users.

However, the tempest API call uses a non existent project, which we
need to change.

Implements bp:validate-project-with-keystone

Change-Id: I825b14addbe7687a4b943acf929284b72a8f9ac0
diff --git a/tempest/api/compute/admin/test_flavors_access_negative.py b/tempest/api/compute/admin/test_flavors_access_negative.py
index bd72d13..9fe1f74 100644
--- a/tempest/api/compute/admin/test_flavors_access_negative.py
+++ b/tempest/api/compute/admin/test_flavors_access_negative.py
@@ -26,6 +26,8 @@
     Add and remove Flavor Access require admin privileges.
     """
 
+    credentials = ['primary', 'admin', 'alt']
+
     @classmethod
     def skip_checks(cls):
         super(FlavorsAccessNegativeTestJSON, cls).skip_checks()
@@ -151,4 +153,4 @@
         self.assertRaises(lib_exc.NotFound,
                           self.admin_flavors_client.remove_flavor_access,
                           new_flavor['id'],
-                          data_utils.rand_uuid())
+                          self.os_alt.servers_client.tenant_id)