Allow running tempest without tenant network resources.
Allow running tempest without tenant network resources.

It fits the Airship deployment where there is neither tenant networks
nor floating ips. It only updates the scenarios and must be completed
by other changes for all the advanced testcases (Rally, Tempest, etc)

Change-Id: I8077400536628ed2349b548efee3c3e165a0a5c3
Signed-off-by: Cédric Ollivier <d48310251a4a484d041bc5d09a9ac4d86d20f793@orange.com>

opnfv/functest,opnfv/functest