Updates tox.ini to publish training guides draft
Updates tox.ini to publish training guides draft

Start publishing training gudies to draft. This also
enables preview during the review on the gerrit interface.

Change-Id: Ibd7090f6ce130fbec73586acece223f81b120122

harrisonfeng/training-guides,Nabs007/training-guides,harrisonfeng/training-guides,harrisonfeng/training-guides,Nabs007/training-guides,Nabs007/training-guides,openstack/training-guides,openstack/training-guides