pgsql: Fix bogus expected output that should have made it quite clear

Log Message:
-----------
Fix bogus expected output that should have made it quite clear that
something was wrong with that tab patch.

Modified Files:
--------------
pgsql/src/test/regress/expected:
prepare.out (r1.16 -> r1.17)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/prepare.out?r1=1.16&r2=1.17)