avoid batch RPC from getting scheduled for cleanup multiple times;  investigation sleuthing done by zhihui@
avoid batch RPC from getting scheduled for cleanup multiple times;  investigation sleuthing done by zhihui@

pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable