Party.lang migration fails from <4.2 to 4.4
The query in Party.__register__ (from r 839f8e57d57e) can not work if the table for PartyLang is not yet created. Indeed r f9d6b409dee8 should have moved this migration script in the PartyLang.__register__. This query should replace the call to migrate property is the column exist on Party.
Spotted on https://groups.google.com/d/msgid/tryton-fr/7cbb19f9-e0a0-fa62-f180-8b011116473d%40champs-libres.coop