egammaAlgs: Pass DataLink to CaloClusterStoreHelper::makeCluster.
Pass a DataLink to CaloClusterStoreHelper::makeCluster rather than a pointer.
This allows us to do the work to construct the DataLink only once, rather than for each cluster.
Pass a DataLink to CaloClusterStoreHelper::makeCluster rather than a pointer.
This allows us to do the work to construct the DataLink only once, rather than for each cluster.