pgsql: Replace linear searches with binary searches in pg_dump's code to

Log Message:
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Replace linear searches with binary searches in pg_dump's code to
lookup objects by OID. Per gripe from nikitathespider.

Modified Files:
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pgsql/src/bin/pg_dump:
common.c (r1.97 -> r1.98)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/common.c?r1=1.97&r2=1.98)