virsh: Offer only persistent domains for autostart
virsh: Offer only persistent domains for autostart

The 'autostart' command accepts only persistent domains. Make the
completer return only those.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>

fabianfreyer/libvirt,eskultety/libvirt,jardasgit/libvirt,zippy2/libvirt,eskultety/libvirt,olafhering/libvirt,fabianfreyer/libvirt,zippy2/libvirt,libvirt/libvirt,nertpinx/libvirt,jfehlig/libvirt,andreabolognani/libvirt,nertpinx/libvirt,crobinso/libvirt,fabianfreyer/libvirt,libvirt/libvirt,jardasgit/libvirt,nertpinx/libvirt,jfehlig/libvirt,andreabolognani/libvirt,libvirt/libvirt,eskultety/libvirt,jfehlig/libvirt,olafhering/libvirt,jardasgit/libvirt,eskultety/libvirt,nertpinx/libvirt,eskultety/libvirt,zippy2/libvirt,libvirt/libvirt,crobinso/libvirt,andreabolognani/libvirt,jardasgit/libvirt,crobinso/libvirt,olafhering/libvirt,olafhering/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,jfehlig/libvirt,nertpinx/libvirt,zippy2/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,crobinso/libvirt