ing: fix bad login with cookie cache

Description of the problem: we are loading an expired cookie. We go to
the login page (redirected by the website, or because of the url stored
in storage. It does not matter).
Next step: we call do_logout, it clear the cookies
Next step: stay_or_go do nothing
Next step: we do a post, without any cookie. The request fail

Solution: force the "go()" after cookie cleaning

modules/ing/browser.py

@@ -77,7 +77,7 @@ class IngBrowser(LoginBrowser):
         assert self.birthday.isdigit()
 
         self.do_logout()
-        self.loginpage.stay_or_go()
+        self.loginpage.go()
 
         self.page.prelogin(self.username, self.birthday)
         self.page.login(self.password)