[banquepopulaire] dangling reference to browser.get_accounts_list

As reported by a Kresus user:

  File "/var/www/kresus/data/weboob-data/modules/1.5/banquepopulaire/module.py", line 105, in iter_accounts

    return self.browser.get_accounts_list()

AttributeError: 'BanquePopulaire' object has no attribute 'get_accounts_list'

It seems like a recent regression, because the user tells that things were working fine until the beginning of the new year.