lxd/storage/drivers/drivers/zfs/volumes: Fixes 10s delay when using VMs with ZFS in snap
lxd/storage/drivers/drivers/zfs/volumes: Fixes 10s delay when using VMs with ZFS in snap

This is caused because /dev/zvol appears to not be populated when using the snap.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

hallyn/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,hallyn/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,atxwebs/lxd,lxc/lxd,atxwebs/lxd,lxc/lxd,atxwebs/lxd,lxc/lxd,atxwebs/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,hallyn/lxd,hallyn/lxd,stgraber/lxd,hallyn/lxd,lxc/lxd,lxc/lxd