[libvirt] [PATCH] Fix sparse volume allocation reporting

I have a sparse volume with a capacity of 1000M, and an allocation of a little over 750M. 'du' prints the correct sizes, but 'virsh vol-dumpxml' shows: <capacity>1048576000</capacity> <allocation>6406307840</allocation> This is because we were calculating the allocation size using the requested fs block size, instead of what stat actually uses as a block size (DEV_BSIZE in sys/params.h). sys/params.h looks to be present in mingw32-runtime, so I didn't add a configure check for it. The attached patch fixes allocation listing for me. Thanks, Cole