According to
http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=dromedary&dt=2014-11-21%2019%3A59%3A50
the order of cascaded drops at one point in the rowsecurity test is not
too stable. This is not terribly surprising since it would depend on
physical row order in pg_depend. I think the easiest fix would be to
adjust the client_min_messages setting so that those messages don't appear
at all.
regards, tom lane