Modifies tempest role to run on instack installs

Allows for use of a custom admin/demo password and net-tenant.
Also downloads the cirros image before uploading it
to glance.

Change-Id: Iafffb564bfeb4c70244e88db628500abd7adf79e
Merge remote-tracking branch 'gerrit/master' into dev/reorg

Conflicts:
	roles/tempest/setup/tasks/setup-tempest.yml

Change-Id: I3d7e259339ee7676a9f1784df8d2e8904b21d085