MAINTAINERS: Update for migrated migration code My previous patches migrated the migration code into migration/ but didn't update MAINTAINERS. Note that does mean that the owner for block-migration.c changes, but I'll ask block people what they want to do. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com>