'Unmanage our volume.
We simply rename with with a prefix of `Unmanaged_`  That\'s it.
:param scvolume: The Dell SC volume object.
:return: Nothing.
:raises VolumeBackendAPIException:'

def unmanage(self, scvolume):

    newname = ('Unmanaged_' + scvolume['name'])
    payload = {}
    payload['Name'] = newname
    r = self.client.put(('StorageCenter/ScVolume/%s' % self._get_id(scvolume)), payload, True)
    if self._check_result(r):
        LOG.info('Volume    %s    unmanaged.', scvolume['name'])
    else:
        msg = (_('Unable    to    rename    volume    %(existing)s    to    %(newname)s') % {'existing': scvolume['name'], 'newname': newname})
        raise exception.VolumeBackendAPIException(data=msg)
