Remove on-disk storage of virtual block devices
Implement retrieving VBD info from /proc
remove VBD delete and flush commands as VBDs go away by themselves when their domains are destroyed
Undo silly design decision by me; namely, to do any checking of values in the Parse classes.
Instead, it should be done in the Command classes, so that the web interface need not duplicate code.
rac61@labyrinth.cl.cam.ac.uk