This set of patches:
- Adds new APIs to support discard in libguestfs.
- Adds discard support to virt-format.
- Adds discard support to virt-sysprep.
- Implements virt-sparsify --in-place.
This is now working, after fixing the rather stupid bug in fstrim.
I've pushed the ones which were ACKed previously + the fstrim fix.
Rich.