locale switched from fr_FR.UTF-8 to fr_FR after upgrade to 2.30.5-0ubuntu4.1

Binary package hint: gdm

My locale was fr_FR.UTF-8.
I upgraded Ubuntu today with the quasi-daily upgrates. The only update of today is gdm 2.30.5-0ubuntu4.1
Next time I logged in:
- a dialog in english after login ask me to rename "Bureau" to "Desktop", "Vidéos" to "Videos"...
- the system is now mostly in english

In fact, the locale is now "fr_FR" instead of "fr_FR.UTF-8". "fr_FR" is not a valid locale (most software do not have LC_MESSAGES for it) so everything defaults to "C" which is english.

locale -a :
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
LANG=fr_FR
LANGUAGE=fr_FR:fr:en_GB:en
LC_CTYPE="fr_FR"
LC_NUMERIC="fr_FR"
LC_TIME="fr_FR"
LC_COLLATE="fr_FR"
LC_MONETARY="fr_FR"
LC_MESSAGES="fr_FR"
LC_PAPER="fr_FR"
LC_NAME="fr_FR"
LC_ADDRESS="fr_FR"
LC_TELEPHONE="fr_FR"
LC_MEASUREMENT="fr_FR"
LC_IDENTIFICATION="fr_FR"
LC_ALL=

This has happened on the two computers I where I did the upgrade. Some others french users have the same problem. http://forum.ubuntu-fr.org/viewtopic.php?id=448782

This is Ubuntu 10.10.
From /var/log/apt/history.log:

Start-Date: 2011-03-31 09:08:08
Upgrade: gdm:amd64 (2.30.5-0ubuntu4+langfixes~maverick1, 2.30.5-0ubuntu4.1)
End-Date: 2011-03-31 09:08:47