[FIX] product.copy(): do it in en_US:

[FIX] product.copy(): do it in en_US:
when implementing our own copy() method, and thus part
of the copy_data() method, we should do it in a consistent
way: copy_data() copy the name in en_US, so we should do
it in en_US too. Otherwise we end up writing the name of
the new product with a user-translated name.

lp bug: https://launchpad.net/bugs/799655 fixed

bzr revid: vmt@openerp.com-20120214143420-7c16betfwlwblgjo