[FIX] website: correct redirect with correct lang

When forcing another language that the current one (the cookie one) in an
url, the requested lang wasn't set correctly in redirect url, but the
cookie was, resulting in multiple redirect which ends with initial lang.

A side effect of this error was the inability to edit website page when
default lang is not en_US and user not in default lang.

The request context must be reset before being used by
`request.redirect` (in `url_for` method).

addons/website/models/ir_http.py

@@ -196,9 +196,9 @@ class Http(models.AbstractModel):
                     if request.lang != request.website.default_lang_code:
                         path.insert(1, request.lang)
                     path = '/'.join(path) or '/'
+                    request.context = context
                     redirect = request.redirect(path + '?' + request.httprequest.query_string)
                     redirect.set_cookie('website_lang', request.lang)
-                    request.context = context
                     return redirect
                 elif url_lang:
                     request.uid = None