Fix "lava-server manage workers add"
Fix "lava-server manage workers add"

Allow to set Worker health (using --health) when creating a worker.
Also fix csv export.

Change-Id: I3b9be45ceaa0dae12bd30723d7675a64a0829450

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