Make python-guestfs NOPRIME & install for libvirt

The libguestfs dependency tree includes a number
of packages that we may not want or work everywhere, such as fuse.

Now python-(lib)guestfs will install from lib/nova_plugins/hypervisor-libvirt

Change-Id: I6c3a614010ee8d65813eec66a56680def622514c
diff --git a/lib/nova_plugins/hypervisor-libvirt b/lib/nova_plugins/hypervisor-libvirt
index 415244f..7f08804 100644
--- a/lib/nova_plugins/hypervisor-libvirt
+++ b/lib/nova_plugins/hypervisor-libvirt
@@ -140,10 +140,12 @@
         install_package kvm
         install_package libvirt-bin
         install_package python-libvirt
+        install_package python-guestfs
     elif is_fedora || is_suse; then
         install_package kvm
         install_package libvirt
         install_package libvirt-python
+        install_package python-libguestfs
     fi
 
     # Install and configure **LXC** if specified.  LXC is another approach to