This PR makes following changes.
- Simplify volume tearDown path for iSCSI and FC using
util.UnmountPath().
- Log lastErr during iscsi connection
If iscsid fails to connect second portal, currently
the error is ignored silently. The lastErr should be
logged to find the root cause of problem.
- Remove iscsi plugin directory after iscsi connection
is successfully closed.
After a volume is unmounted from pod and worker node,
cluster admin or external-provisioner might delete
the disk from storage, therefore block device on
the node should be cleaned up beforehand.
The photon volume plugin already has same functionality.
Fixes#49392