pgsql: Remove erroneous claim about use of pg_locks.objid for advisory

Remove erroneous claim about use of pg_locks.objid for advisory locks.

The correct information appears in the text, so just remove the statement
in the table, where it did not fit nicely anyway.  (Curiously, the correct
info has been there much longer than the erroneous table entry.)
Resolves problem noted by Daniele Varrazzo.

In HEAD and 9.1, also do a bit of wordsmithing on other text on the page.

Branch
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REL9_0_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/d16ebde58275d848968e758ec643efc8ce64c8fa

Modified Files
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doc/src/sgml/catalogs.sgml |    5 +----
1 files changed, 1 insertions(+), 4 deletions(-)