Correctly implement handleOperatorRemoved

[MatusKysel]

We need to re-implement handleOperatorRemoved as it currently doing nothing

	// TODO: In original handler we didn't delete operator data, so this behavior was preserved. However we likely need to.
	// TODO: Delete operator from all the shares.
	//	var shares []Share
	//	for _, s := range nodeStorage.Shares().List() {
	//		// if operator in committee, delete him from it:
	//		//     shares = append(shares, s)
	//	}
	//	nodeStorage.Shares().Save(shares)
	// err = eh.nodeStorage.DeleteOperatorData(txn, od.ID)
	// if err != nil {
	// 	return err
	// }