The management can query the current migration capabilities using
query-migrate-capabilities QMP command.
The user can use 'info migrate_capabilities' HMP command.
Currently only XBZRLE capability is available.
Signed-off-by: Orit Wasserman <owasserm@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>