The output of "virsh capabilities" was not conformant to the
capability.rng schema. Add the missing element to the schema.
Fixes: c647bf29afb9890c792172ecf7db2c9c27babbb6
Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Signed-off-by: Jim Fehlig <jfehlig@suse.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>