BUG #7677: listen_address 'localhost' listens not to IPv6 ::1

The following bug has been logged on the website:

Bug reference: 7677
Logged by: Peter Weber
Email address: bugs(at)ttyhoney(dot)com
PostgreSQL version: 9.1.6
Operating system: GNU/Linux (Fedora 17)
Description:

Hello!
I just started to use PostgreSQL here, and followed this guide[see 1]. As I
am currently just playing around I wondered, if I can use IPv6. My network
is not IPv6 capabable, but my machine is. So I used "[::1]" instead if
"localhost" or "127.0.0.1". I doesn't work with "[::1]".

Told me, that PostgreSQL is only listening to IPv4:
$ ss -ln
127.0.0.1:5432 *:*

So I modified the postgresql.conf:
FROM
#listen_addresses = 'localhost'
TO
listen_addresses = '::'

And PostgresSQL starts to listen to IPv6:
$ ss -ln
:::5432 :::*

What I expect:
localhost means 127.0.0.1 if IPv4 is available OR ::1 if IPv6 is available.
This is a logical OR, that means booth at the same time are possible.

Thank you
Peter

[1]http://jdbc.postgresql.org/documentation/91/connect.html