Show filename of disk attached in log

Signed-off-by: Carlos Aguado Sanchez <carlos.aguado@epfl.ch>
Reorder logic to cleanup snapshots and resume

The taking of snapshots happens with the VM paused. However the deletion
of previous snapshots happens with the VM running. This commit addresses
this very point by consolidating all snapshot operations into the paused
state and resumes only happens after.

Signed-off-by: Carlos Aguado Sanchez <carlos.aguado@epfl.ch>