pgsql: doc: Fix mistakes in the most recent set of release notes.

doc: Fix mistakes in the most recent set of release notes.

Improve description of the vacuum_freeze_table_age bug (it's much more
serious than we realized at the time the fix was committed), and correct
attribution of pg_upgrade -O/-o fix (Marti Raudsepp contributed that,
but Bruce forgot to credit him in the commit log).

No need to back-patch right now, it'll happen when the next set of
release notes are prepared.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/335c5e9206b40c2fac3945db2499a57b948cc996

Modified Files
--------------
doc/src/sgml/release-8.4.sgml | 6 +++---
doc/src/sgml/release-9.0.sgml | 6 +++---
doc/src/sgml/release-9.1.sgml | 6 +++---
doc/src/sgml/release-9.2.sgml | 8 ++++----
4 files changed, 13 insertions(+), 13 deletions(-)