Fix bug #1251883 -  Offline heartbeat not applied for all status.
Fix bug #1251883 -  Offline heartbeat not applied for all status.

Status such as the following are considered to mark a device offline:

* OFFLINE
* OFFLINING
* RETIRED
* UNREACHABLE

Change-Id: If6b0993a92d28ca9411572d789c90c737f6f0248
Reviewed-on: https://staging.review.linaro.org/480
Reviewed-by: lava-bot <f1c518755f92a4c3b69132fe31fc3cc1dae5545f@linaro.org>
Reviewed-by: Stevan Radaković <33f9dd6baa06800e337711f1ba9a74a68b30bd64@linaro.org>

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