BUG #4320: Describe table on 8.2.9 server fail

The following bug has been logged online:

Bug reference:      4320
Logged by:          Alexandre Payment
Email address:      alex.payment@gmail.com
PostgreSQL version: 8.3.3
Operating system:   Ubuntu Linux 8.04
Description:        Describe table on 8.2.9 server fail
Details:

Connected to a 8.2.9 non-local server with psql version 8.3.3 and entering
the following command (describe table t_ann):

\d t_ann

this error occur:
ERROR:  column t.tgconstraint does not exist
LINE 3: WHERE t.tgrelid = '16627' AND t.tgconstraint = 0

When connect with psql version 8.2.9 the describe command work perfectly.