apparmor, libvirtd: Allow libxl-save-helper to run on Debian/Ubuntu

On Debian/Ubuntu the libxl-save-helper (used when saving/restoring
a domain through libxl) is located under /usr/lib/xen-<version>/bin.

Bug-Ubuntu: https://bugs.launchpad.net/bugs/1334195Signed-off-by: NChristian Ehrhardt <christian.ehrhardt@canonical.com>
Signed-off-by: NStefan Bader <stefan.bader@canonical.com>

examples/apparmor/usr.sbin.libvirtd

@@ -50,6 +50,7 @@
   /{usr/,}lib/udev/scsi_id PUx,
   /usr/{lib,lib64}/xen-common/bin/xen-toolstack PUx,
   /usr/{lib,lib64}/xen/bin/* Ux,
+  /usr/lib/xen-*/bin/libxl-save-helper PUx,
 
   # force the use of virt-aa-helper
   audit deny /{usr/,}sbin/apparmor_parser rwxl,