Temporarily disable use of TEMPEST_CONF_DIR
Temporarily disable use of TEMPEST_CONF_DIR

This is caused by an issue with tox [1]

[1] https://bitbucket.org/hpk42/tox/issues/285/tox-220-breaks-some-toxini-config-files

Change-Id: Ieda8d3de4cbdb4ba161e8083dbf7fcb119a517ee
Related-bug: 1515335

openstack/networking-vsphere,VTabolin/networking-vsphere,stackforge/networking-vsphere,ekosareva/networking-vsphere,ekosareva/networking-vsphere,stackforge/networking-vsphere,Mirantis/vmware-dvs,ekosareva/vmware-dvs,ekosareva/vmware-dvs,openstack/networking-vsphere,Mirantis/vmware-dvs,VTabolin/networking-vsphere