pgsql: Remove unnecessary and version-sensitive dependence on the exact

Log Message:
-----------
Remove unnecessary and version-sensitive dependence on the exact set of
column names to be found in a sequence. Per gripe from Bruce.

Tags:
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REL8_4_STABLE

Modified Files:
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pgsql/src/bin/psql:
describe.c (r1.218 -> r1.218.2.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/describe.c?r1=1.218&r2=1.218.2.1)