Fix example of hyperslab block coordinate printing

[grimbough]

No sure if you welcome community pull requests, but hopefully this is helpful.

I've notice a small bug in the h5_vds.c example, where it prints the coordinates of the hyperslab blocks. This is the current code:

for (l=0; l<nblocks; l++) {
    printf("(");
    for (k=0; k<RANK2-1; k++) 
        printf("%d,", (int)buf[k]);
    printf("%d) - (", (int)buf[k]);
    for (k=0; k<RANK2-1; k++) 
        printf("%d,", (int)buf[RANK2+k]);
     printf("%d)\n", (int)buf[RANK2+k]);
}

Although it loops over the number of blocks, it doesn't use the block counter when printing the information, and so will just show the coordinates of the first block over and over. The patch is intended to enable printing the coordinates for all blocks.

This behaviour isn't obvious in the current example as none of the hyperslabs consist of more than one block. However, I ended up at the example from H5S_GET_SELECT_HYPER_BLOCKLIST and was trying to use it to understand my own program, where this printing had me confused for a while. Hopefully this might help anyone else copy/pasting the example into their own code in the future.

[epourmal]

Thank you for your contribution! Yes, we do encourage PRs from community. The patch looks good to me!