Avoid initializing unnecessary objects in method getBlockRecoveryCommand

       else {
        rBlock = new RecoveringBlock(primaryBlock, recoveryInfos,
            uc.getBlockRecoveryId());
        if (b.isStriped()) {
          rBlock = new RecoveringStripedBlock(rBlock,
              uc.getBlockIndicesForSpecifiedStorages(storageIdx),
              ((BlockInfoStriped) b).getErasureCodingPolicy());
        }