Remove pip install of pyscss in Horizon
Remove pip install of pyscss in Horizon

Because of the correction of the dependney repos in RDO, pyscss
no longer needs to be installed via pip.

Change-Id: Ide0a0181a9b1353a043956ab9849a2d261f1c243
Closes-Bug: #1497436

rajalokan/kolla,fdumpling/kolla,tonyli71/kolla,stackforge/kolla,fdumpling/kolla,dardelean/kolla-ansible,limamauricio/mykolla,openstack/kolla,negronjl/kolla,dardelean/kolla-ansible,mrangana/kolla,nihilifer/kolla,rajalokan/kolla,mandre/kolla,rahulunair/kolla,coolsvap/kolla,stackforge/kolla,toby82/kolla,toby82/kolla,limamauricio/mykolla,mandre/kolla,toby82/kolla,dardelean/kolla-ansible,GalenMa/kolla,mrangana/kolla,openstack/kolla,stackforge/kolla,limamauricio/mykolla,coolsvap/kolla,rahulunair/kolla,coolsvap/kolla,mandre/kolla,intel-onp/kolla,GalenMa/kolla,rajalokan/kolla,fdumpling/kolla,intel-onp/kolla,nihilifer/kolla,negronjl/kolla,negronjl/kolla,tonyli71/kolla