[pike] Allow to set ionice level for lvm volume clear

for now implemented in downstream

pillar item is compute.lvm.volume_clear_ionice_level

This is followup to I3d00e1b4c8752133ef395797045c3f2a3afae94d
enabiling this feature in Pike too.

Change-Id: Id93693eb59cdbad79ff0ea67e7864ea380b08da2
Related-Issue: PROD-30537
3 files changed