BUG #6385: extract epoch at timezone returns wrong value

The following bug has been logged on the website:

Bug reference: 6385
Logged by: Sreeraj S
Email address: sreeraj(at)ordyn(dot)com
PostgreSQL version: 9.1.2
Operating system: Windows Vista Professional
Description:

Below is given psql output - I am in timezone UTC+05:30 (India) as shown by
select now() output below.

When I give "SELECT extract(epoch from now() );" the output is
1325872658.xxx

I would expect a slightly incremented value when after a few seconds I give
the command "SELECT extract(epoch from now() at time zone 'utc+05:30');" .
Nut I get the value 1325833067.xxx which is the value for utc-05:30 !!!

And when I give "SELECT extract(epoch from now() at time zone
'utc-05:30');", I get 1325872672.xxx which is what is expected if I
specified timezone +05:30 !!!

----- psql extract below ------

ordprdlic=> select now();
now
-------------------------------
2012-01-06 23:27:35.663+05:30
(1 row)

ordprdlic=> SELECT extract(epoch from now() );
date_part
----------------
1325872658.608
(1 row)

ordprdlic=> SELECT extract(epoch from now() at time zone 'utc+05:30');
date_part
----------------
1325833067.073
(1 row)

ordprdlic=> SELECT extract(epoch from now() at time zone 'utc-05:30');
date_part
----------------
1325872672.977
(1 row)