This is an utility for managing SCSI Enclosure Services (SES) device.
For now only one command is supported "locate" which will change the test of the
external LED associated to a given disk.
Usage if the following:
sesutil locate disk [on|off]
Disk can be a device name: "da12" or a special keyword: "all".
Reviewed by: mav
MFC after: 1 month
Relnotes: yes
Sponsored by: gandi.net
Differential Revision: https://reviews.freebsd.org/D3544