package mysql-server-5.5 5.5.34-0ubuntu0.12.04.2 failed to install/upgrade: le sous-processus script post-installation installé a retourné une erreur de sortie d'état 1

From log:

Paramétrage de mysql-server-5.5 (5.5.34-0ubuntu0.12.04.2) ...
140117 14:30:59 [Note] Plugin 'FEDERATED' is disabled.
140117 14:30:59 InnoDB: The InnoDB memory heap is disabled
140117 14:30:59 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140117 14:30:59 InnoDB: Compressed tables use zlib 1.2.3.4
140117 14:30:59 InnoDB: Initializing buffer pool, size = 128.0M
140117 14:30:59 InnoDB: Completed initialization of buffer pool
140117 14:30:59 InnoDB: highest supported file format is Barracuda.
140117 14:30:59 InnoDB: Waiting for the background threads to start
140117 14:31:00 InnoDB: 5.5.34 started; log sequence number 1595675
140117 14:31:01 InnoDB: Starting shutdown...
140117 14:31:01 InnoDB: Shutdown completed; log sequence number 1595675
start: Job failed to start
invoke-rc.d: initscript mysql, action "start" failed.
dpkg : erreur de traitement de mysql-server-5.5 (--configure) :
 le sous-processus script post-installation installé a retourné une erreur de sortie d'état 1
dpkg : des problèmes de dépendances empêchent la configuration de mysql-server :
 mysql-server dépend de mysql-server-5.5 ; cependant :
 Le paquet mysql-server-5.5 n'est pas encore configuré.
dpkg : erreur de traitement de mysql-server (--configure) :
 problèmes de dépendances - laissé non configuré

Triage note: this is from precise-proposed, uploaded recently.

Thank you for taking the time to report this bug and helping to make Ubuntu better, and for testing proposed updates.

It's not clear to me if this is a bug in the proposed update or not.

Since it seems likely to me that this is a local configuration problem, rather than a bug in Ubuntu, I'm marking this bug as Incomplete.

If this is indeed a local configuration problem, you can find pointers to get help for this sort of problem here: http://www.ubuntu.com/support/community

Or if you believe that this is really a bug, then you may find it helpful to read "How to report bugs effectively" http://www.chiark.greenend.org.uk/~sgtatham/bugs.html. We'd be grateful if you would then provide a more complete description of the problem, explain why you believe this is a bug rather than a problem specific to your system, and then change the bug status back to New.

Actually, someone pointed out what Error: [Errno 2] Aucun fichier ou dossier de ce type: '/etc/mysql/my.cnf' means on IRC.

This suggests that you have a local configuration problem, so I'm marking this bug as Invalid.

If this is indeed a local configuration problem, you can find pointers to get help for this sort of problem here: http://www.ubuntu.com/support/community

Or if you believe that this is really a bug, then you may find it helpful to read "How to report bugs effectively" http://www.chiark.greenend.org.uk/~sgtatham/bugs.html. We'd be grateful if you would then provide a more complete description of the problem, explain why you believe this is a bug rather than a problem specific to your system, and then change the bug status back to New.

Sorry for the incorrect bug declaration.
After restoring the file /etc/mysql/my.cnf, I have installed without error the package (with dpkg --configure package).