[RHHI] Storage Domain is full and unable to remove disk to free up space

Issue

• Let the Storage Domain become 100% full and can not clear space

• When deleting a VM disk get the following error in the vdsm logs

  2020-03-18 12:11:54,155-0400 INFO  (jsonrpc/0) [vdsm.api] START deleteImage(sdUUID=u'2881e321-b95b-40c8-9874-a21a8eeb3167', spUUID=u'4f8f54b4-9dad-11e9-ad2b-00163e39e42b', imgUUID=u'ebfa8fb7-3a63-484e-ad54-2ca789fd6feb', postZero=u'false', force=u'false', discard=False) from=::ffff:10.8.117.7,56954, flow_id=57566b8b-e4d1-4522-9c75-6365d5866a11, task_id=d9c34302-2961-420e-9fa5-4497d60491f8 (api:48)
  2020-03-18 12:11:54,440-0400 INFO  (jsonrpc/0) [vdsm.api] FINISH deleteImage error=Could not remove all image's volumes: (u'ebfa8fb7-3a63-484e-ad54-2ca789fd6feb [Errno 28] No space left on device',) from=::ffff:10.8.117.7,56954, flow_id=57566b8b-e4d1-4522-9c75-6365d5866a11, task_id=d9c34302-2961-420e-9fa5-4497d60491f8 (api:52)
  2020-03-18 12:11:54,440-0400 ERROR (jsonrpc/0) [storage.TaskManager.Task] (Task='d9c34302-2961-420e-9fa5-4497d60491f8') Unexpected error (task:875)
  2020-03-18 12:11:54,440-0400 INFO  (jsonrpc/0) [storage.TaskManager.Task] (Task='d9c34302-2961-420e-9fa5-4497d60491f8') aborting: Task is aborted: "Could not remove all image's volumes: (u'ebfa8fb7-3a63-484e-ad54-2ca789fd6feb [Errno 28] No space left on device',)" - code 256 (task:1181)