fix empty rdd
fix empty rdd

dogeyes/dpark,yhj630520/dpark,yhj630520/dpark,zzl0/dpark,windreamer/dpark,daishaowei/dpark,windreamer/dpark,304471720/dpark,douban/dpark,quxiaolong1504/dpark,304471720/dpark,mageia/dpark,daishaowei/dpark,quxiaolong1504/dpark,smarthomekit/dpark,dogeyes/dpark,junmoa/dpark,douban/dpark,dogeyes/dpark,Mignet/dpark,windreamer/dpark,junmoa/dpark,windreamer/dpark,veritynoob/dpark,ee08b397/dpark,Mignet/dpark,douban/dpark,douban/dpark,yhj630520/dpark,veritynoob/dpark,smarthomekit/dpark,veritynoob/dpark,oceanjack/dpark,smarthomekit/dpark,mageia/dpark,yanheven/dpark,douban/dpark,fe11x/dpark,oceanjack/dpark,yanheven/dpark,zzl0/dpark,fe11x/dpark,304471720/dpark