pgsql: Update regression tests for new referential integrity error

Log Message:
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Update regression tests for new referential integrity error message
wording ("table" added).

Modified Files:
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pgsql/src/test/regress/expected:
foreign_key.out (r1.40 -> r1.41)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/foreign_key.out.diff?r1=1.40&r2=1.41)