Fix cleanup-dispvms script
Fix cleanup-dispvms script

qubesadmin.Qubes().domains do not support indexing by VM object.

QubesOS/qubes-issues#3037

marmarek/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,QubesOS/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin