migration: v1 health-check are not used anymore
migration: v1 health-check are not used anymore

That's not needed anymore to show device with both v1 and v2 health checks.
v1 health checks will be removed in 2017.12 when the database will be cleaned.

Change-Id: Icb4f8c8249cb514d5659f5afe1bccc0d9fd917eb

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