BUG #5928: PD_ALL_VISIBLE flag incorrectly set warning messages

The following bug has been logged online:

Bug reference:      5928
Logged by:          Lane Stevens
Email address:      lane@mobilsense.com
PostgreSQL version: 8.4.4
Operating system:   CentOS
Description:        PD_ALL_VISIBLE flag incorrectly set warning messages
Details:

A series of messages similar to the following were logged:

pgsql.log:Mar 14 16:38:44 bo01 preprod[5462]: [2-1] eval25WARNING:
PD_ALL_VISIBLE flag was incorrectly set in relation "pg_statistic" page 45

This happened at least one other time on Jan 10 with the same version of the
database.  So far I have been unable to replicate the error.

Kernel is:  2.6.18-164.15.1.el5
postgresql is:  postgresql-8.4.4-2PGDG.el5