Align session codec max-age with the 7-day cap (closes #108)

internal/middleware/middleware.go

@@ -214,11 +214,11 @@ func (s *Middleware) RequireAuth() func(http.Handler) http.Handler {
 			// handler runs, while the headers are still ours to
 			// write.
 			if s.session.Touch(sess) {
-				err = s.session.Save(r, w, sess)
-				if err != nil {
+				saveErr := s.session.Save(r, w, sess)
+				if saveErr != nil {
 					s.log.Error(
 						"auth middleware: failed to refresh session",
-						"error", err,
+						"error", saveErr,
 					)
 				}
 			}