2019-09-26: InfluxDB nodes were not using the persistent data disk

InfluxDB nodes were not using the persistent data disk attached to them, instead, they were using the boot disk. This seems like an oversight from the time these nodes were provisioned, as their Terraform configuration should've specified /var/lib/influxdb as the persistent disk path.

Since we only have 4 of these nodes, a manual fix was applied:

1. Chef configuration was updated to point to the persistent disk
2. chef-client was stopped on all nodes
3. Node by node, influxd was stopped, data dir was moved to the persistent disk, then chef-client was executed