Fix the issue non-admin user failed to list trusts
Fix the issue non-admin user failed to list trusts

Openstacksdk did not pass filters(trustor_user_id or trustee_user_id)
to keystone, this made non-admin user failed to list trusts with the
error "admin_required". Please see the code at keystone side:
http://git.openstack.org/cgit/openstack/keystone/tree/keystone/trust/controllers.py#n193

Change-Id: I54bdf75cae7713d2faa1cec98c894ddd4c6a8581

openstack/python-openstacksdk,openstack/python-openstacksdk,dtroyer/python-openstacksdk,stackforge/python-openstacksdk,briancurtin/python-openstacksdk,dtroyer/python-openstacksdk,briancurtin/python-openstacksdk,stackforge/python-openstacksdk