Add argument to disable data upload
Add argument to disable data upload

Added an --offline argument which will prevent Tempest results
from being uploaded to the Refstack server if used.

Change-Id: I40df179288354a6eb7fac1d0ed634d722a780817
Story: https://storyboard.openstack.org/#!/story/190

stackforge/refstack-client,stackforge/refstack-client,openstack/refstack-client,openstack/refstack-client