Do not assign admin to service users
Do not assign admin to service users

As pointed out by Brant Knudson in change [1], the sample policy file
allows the service user to validate tokens [2], so service users don't
need 'admin' role, they only need 'service'.

This patch adds the 'service' role creation to our tools/sample_data.sh
and updates service roles to it rather than 'admin'.

[1] Iebc4f6b005e0466fe60691d964c7dea0e0eee947
[2] http://git.openstack.org/cgit/openstack/keystone/tree/etc/policy.json#n94

Change-Id: I3336514f7a2e1e749908d92b693d765c3ed48f51

ilay09/keystone,himanshu-setia/keystone,klmitch/keystone,openstack/keystone,dims/keystone,cernops/keystone,rajalokan/keystone,ilay09/keystone,openstack/keystone,mahak/keystone,mahak/keystone,klmitch/keystone,openstack/keystone,dims/keystone,rajalokan/keystone,himanshu-setia/keystone,cernops/keystone,ilay09/keystone,rajalokan/keystone,mahak/keystone