Fix offline message when a device is set offline whilst running. Offline message is taken from Offlining reason.
Fix offline message when a device is set offline whilst running.
Offline message is taken from Offlining reason.

Change-Id: I12092a71e08ffc0f398229187f591886d1247a52

OSSystems/lava-server,Linaro/lava-server,OSSystems/lava-server,OSSystems/lava-server,Linaro/lava-server,Linaro/lava-server,Linaro/lava-server