Grant access to helpers

Apparmor must not prevent access to required helper programs. The following
helpers should be allowed to run in unconfined execution mode:

 - libvirt_parthelper
 - libvirt_iohelper

examples/apparmor/usr.sbin.libvirtd

@@ -58,6 +58,8 @@
   audit deny /sys/kernel/security/apparmor/.* rwxl,
   /sys/kernel/security/apparmor/profiles r,
   /usr/{lib,lib64}/libvirt/* PUxr,
+  /usr/{lib,lib64}/libvirt/libvirt_parthelper ix,
+  /usr/{lib,lib64}/libvirt/libvirt_iohelper ix,
   /etc/libvirt/hooks/** rmix,
   /etc/xen/scripts/** rmix,