pgsql: Unbreak regression tests (Peter's recent checkin to

Log Message:
-----------
Unbreak regression tests (Peter's recent checkin to executor/spi.c did
not update some error message text).

Modified Files:
--------------
pgsql/src/test/regress/expected:
foreign_key.out (r1.37 -> r1.38)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/foreign_key.out.diff?r1=1.37&r2=1.38)
triggers.out (r1.17 -> r1.18)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/triggers.out.diff?r1=1.17&r2=1.18)