Load kvm modules after libvirt is installed

Nova compute fails to start on bare metal when kvm modules are not
loaded after libvirt is installed. This patch adds kvm.modules execution
after libvirt is installed.

Fixes bz#893669

Change-Id: Ia1aa17c57fb409dcd987813390c36359111316a9
Merge "Load kvm modules after libvirt is installed"