If there are quite a few nearly empty partitions per disk you might see
some write load even if your cluster is unused. The auditor will update
the status file after every partition, and this might happen multiple
times within a second if there is not much data stored yet.
This patch throttles updates, and will only write out an updated status
if the file was last updated more than a minute ago.
Closes-Bug: 1631352
Change-Id: Ib61ec9cd945e6b2d28756f6ca47801674a7e6060