Add missing apt-get clean in Ubuntu base image
Add missing apt-get clean in Ubuntu base image

TrivialFix

Change-Id: Ibd4ba9dbe2cadb304e027b60d5b7378416719d12

stackforge/kolla,stackforge/kolla,GalenMa/kolla,nihilifer/kolla,coolsvap/kolla,coolsvap/kolla,mandre/kolla,mandre/kolla,GalenMa/kolla,mrangana/kolla,rahulunair/kolla,openstack/kolla,rahulunair/kolla,intel-onp/kolla,dardelean/kolla-ansible,dardelean/kolla-ansible,coolsvap/kolla,dardelean/kolla-ansible,stackforge/kolla,mrangana/kolla,openstack/kolla,mandre/kolla,intel-onp/kolla,nihilifer/kolla