PostgreSQL error on DISTINCT query

The code that (re)populates the active_translation table, executes the following query (with an arbitrary number of nids):

SELECT DISTINCT(nid), nid, nid FROM node WHERE tnid = 0 OR tnid IS NULL ORDER BY tnid

PostgreSQL cannot work with this combination of DISTINCT and ORDER BY.
(The exact error is: 'column "node.tnid" must appear in the GROUP BY clause or be used in an aggregate function')

This patch fixes the problem by just getting rid of the DISTINCT 'modifier'. After all, it should not be necessary on the table 'node' because node.nid is its primary key => has unique values.

(IF node.nid were not unique, the following query would yield the same result and work on all SQL92 compliant databases:
SELECT nid, nid, nid FROM node WHERE tnid = 0 OR tnid IS NULL GROUP BY nid ORDER BY Min(tnid)
...but that is not an issue.)

A remark: since this query is only fired once after enabling the module or changing form settings, I don't think performance issues are a huge factor here... (Not that I think the query with DISTINCT runs faster, I don't know that.)

Remark #2: the patch is applied to a source file where http://drupal.org/node/499972 was already applied.