change redis to all time

app/controller/course/v4/user.js

@@ -29,7 +29,7 @@ class UserController extends Controller {
     // 存储缓存标识
     const user_uuid = user.uuid;
     const key = 'course_v4_user_session_' + user_uuid;
-    await app.memcache.set(key, { user_uuid, openid, session_key }, 86400 * 7);
+    await app.memcache.set(key, { user_uuid, openid, session_key });
     const auth_token = ctx.helper.md5(openid + user_uuid + 'jbwl');
     ctx.set('uuid', key);
     ctx.set('auth_token', auth_token);