Missing ADMIN_USER in sample_data.sh
Missing ADMIN_USER in sample_data.sh

When moving from keystone to openstack client, the initialization of
the ADMIN_USER variable was removed, making the script to fail.

Change-Id: Iee2d5b1cbed6c93e335a4b4dbad3034a2f8e29ed

dstanek/keystone,cernops/keystone,vivekdhayaal/keystone,mahak/keystone,ajayaa/keystone,maestro-hybrid-cloud/keystone,himanshu-setia/keystone,mahak/keystone,openstack/keystone,idjaw/keystone,ajayaa/keystone,roopali8/keystone,dims/keystone,rajalokan/keystone,mahak/keystone,takeshineshiro/keystone,vivekdhayaal/keystone,openstack/keystone,cernops/keystone,roopali8/keystone,jonnary/keystone,ilay09/keystone,dstanek/keystone,jamielennox/keystone,himanshu-setia/keystone,klmitch/keystone,jonnary/keystone,ilay09/keystone,jamielennox/keystone,vivekdhayaal/keystone,takeshineshiro/keystone,rajalokan/keystone,idjaw/keystone,dims/keystone,rajalokan/keystone,openstack/keystone,ilay09/keystone,klmitch/keystone,dstanek/keystone,maestro-hybrid-cloud/keystone