Fix STALE_TOKEN_DURATION usage
Fix STALE_TOKEN_DURATION usage

Change-Id: I9856684d93d8b45310e599863553a020180aa509
Signed-off-by: Julien Danjou <5c682c2d1ec4073e277f9ba9f4bdf07e5794dabe@danjou.info>

citrix-openstack-build/keystoneauth,sileht/keystoneauth,jamielennox/keystoneauth