[FIX] web: traceback on accessing home page

before this commit, after running an older version,
 lets say odoo 14 and trying to access 16 in the
 same browser return traceback without redirecting
  to db selector page

 and this happens due to the missing env in request,
 which returns as None.

 after this commit, no traceback wont be shown and
 will open the db selector page

closes odoo/odoo#118851

X-original-commit: 900303c18243e3b97414b3dbf5eb7ee5b8c9c080
Signed-off-by: Julien Castiaux (juc) <juc@odoo.com>

addons/web/controllers/home.py

@@ -29,7 +29,7 @@ class Home(http.Controller):
 
     @http.route('/', type='http', auth="none")
     def index(self, s_action=None, db=None, **kw):
-        if request.session.uid and not is_user_internal(request.session.uid):
+        if request.db and request.session.uid and not is_user_internal(request.session.uid):
             return request.redirect_query('/web/login_successful', query=request.params)
         return request.redirect_query('/web', query=request.params)