[FIX]product: add store=dict to field name_template

bzr revid: csn@openerp.com-20130412130856-3g5e67v2r7y6ep5v
[REF]product: remove one extra loop

bzr revid: csn@openerp.com-20130415102121-u74t7zd3zct3q3ts
[IMP] only recompute name_template if product_tmpl_id changes
PEP8
improve looping efficiency
Merge pull request #61 from acsone/7.0-imp-name_template_store

7.0 [IMP] product: improve store for field name_template