BUG #2314: The Order changed?

The following bug has been logged online:

Bug reference:      2314
Logged by:          L.Jumadi
Email address:      j0e@telkom.net
PostgreSQL version: 8.1.3
Operating system:   SimplyMepis 3.4.3 with kernel 2.6.15.2
Description:        The Order changed?
Details:

I have a table named test with field like this:
ocode varchar(8), code varchar(8) with primary key
at ocode.With data like this:
ocode   code
'test'    '-0'
'test'    '-1'
'test'    '1'
'test'    '2'
I give the command in the psql like this:
SELECT * FROM test ORDER BY code;
the result is like this:
ocode   code
test    -0
test    1
test    -1
test    2
When I use 8.0.1 version this command gives me result
like this
ocode   code
test    -0
test    -1
test    1
test    2
The question is this a bug?or there is changes in the
way postgreSQL order the field? Thank's in advance