Call removeJob after job failure instead of killing the Master

Again related to my recent incident of being dumb, when executors couldn't be started after 10 times (MAX_NUM_RETRY), the Master threw an exception and the whole cluster died.

This was fairly surprising to me; I was expecting the master/slaves to stay up.

My naive understanding of Master makes it look like just calling removeJob is sensible and the cluster can keep on running.

Does this seem right?