Why not add executor state when report slave usage

[Du, Fan]

When Qos controller make estimations and corrections based on current 
slave executor usages,
the current schema in ResourceUsage does not include executor state, 
IMO,the usages only useful
for estimating resource slack and applying corrections is from RUNNING 
executors, MESOS-4753
is created for this without any feedback, pls correct me if I missed 
something obvious.

Thanks