[Install] Fix installation script
[Install] Fix installation script

This is expected to unlock our gate-rally-install-* jobs

Change-Id: Id1e6ee88560883bb895fc7f561ef210723fff7ad

openstack/rally,vganapath/rally,gluke77/rally,gluke77/rally,vganapath/rally,openstack/rally,eonpatapon/rally,eonpatapon/rally,openstack/rally,yeming233/rally,eayunstack/rally,eayunstack/rally,gluke77/rally,openstack/rally,vganapath/rally,vganapath/rally,gluke77/rally,yeming233/rally,eayunstack/rally