Improve developer docs to turn off libvirt
Improve developer docs to turn off libvirt

Tell folks to turn off libvirt on their host.

Change-Id: I4ca9a466cd14bd7a88880299f56ea0eba343b6c8

fdumpling/kolla,chenzhiwei/kolla,mandre/kolla,negronjl/kolla,stackforge/kolla,LoHChina/kolla,openstack/kolla,chenzhiwei/kolla,jakedahn/kolla,meticulo3366/kolla,mandre/kolla,bdastur/kolla,limamauricio/mykolla,invenfantasy/kolla,fdumpling/kolla,rajalokan/kolla,mrangana/kolla,brk3/kolla,GalenMa/kolla,mandre/kolla,toby82/kolla,jakedahn/kolla,rahulunair/kolla,invenfantasy/kolla,LoHChina/kolla,coolsvap/kolla,fdumpling/kolla,HackToday/kolla,dardelean/kolla-ansible,dardelean/kolla-ansible,limamauricio/mykolla,openstack/kolla,jakedahn/kolla,coolsvap/kolla,chenzhiwei/kolla,GalenMa/kolla,intel-onp/kolla,dardelean/kolla-ansible,tonyli71/kolla,nihilifer/kolla,HackToday/kolla,brk3/kolla,invenfantasy/kolla,HackToday/kolla,stackforge/kolla,negronjl/kolla,intel-onp/kolla,LoHChina/kolla,toby82/kolla,coolsvap/kolla,tonyli71/kolla,negronjl/kolla,bdastur/kolla,limamauricio/mykolla,meticulo3366/kolla,rajalokan/kolla,stackforge/kolla,toby82/kolla,rajalokan/kolla,rahulunair/kolla,nihilifer/kolla,mrangana/kolla