[FIX] claim: when copying a claim, set it to draft stage

Please don't pass a dict to update(), it takes keywargs, no need to create an intermediary dict.
Plus it can be done by passing keywargs to the dict() constructor.
Also use the same `'%s (copy)'` term (including 1 space) as used everywhere else, so it gets translated.  

We get the same copy/pasted stuff in all copy() methods, might as well do them properly.
In v8 most of this [will be removed](https://github.com/odoo-dev/odoo/tree/master-apiculture-o2mnocopy).

For example:

    def copy(self, cr, uid, id, default=None, context=None):
        claim = self.browse(cr, uid, id, context=context)
        default = dict(default or {},
                       stage_id=self._get_default_stage_id(cr, uid, context=context),
                       name=_('%s (copy)') % claim.name)
        return super(crm_claim, self).copy(cr, uid, id, default, context=context)