Google App Engine-Redislabs Go运行时生产错误-无效的内存地址或nil指针取消引用

I'm using the Redis Cloud service (from Redis Labs) on Google App engine Go Runtime , and I get the above mentioned error when I try getting a key that doesn't exist. The code works fine on the local test server, but panics in production.

 c, err := redis.Dial("tcp", "pub-redis-myredis:<myport>")
_, err = c.Do("AUTH", "password") 
value, err := c.Do("GET", "foo4")

if value == nil {
    log.Infof(contextOfAppEngineWhereServerIsRunning, "value not found in redislabs")

} 

The log shows that the panic is in the line _, err = c.Do("AUTH", "password")