BUG #7722: extract(epoch from age(...)) appears to be broken

The following bug has been logged on the website:

Bug reference:      7722
Logged by:          Artem Anisimov
Email address:      aanisimov@inbox.ru
PostgreSQL version: 9.2.1
Operating system:   Slackware Linux 14.0/amd64
Description:        =


The following to queries give the same result (first arguments to age()
differ in the day number only, second arguments are identical):

select extract(epoch from age('2012-11-23 16:41:31', '2012-10-23
15:56:10'));

and

select extract(epoch from age('2012-11-22 16:41:31', '2012-10-23
15:56:10'));

The problem can also be reproduced in pgsql 9.1.4 of Fedora 17.