[Verify] Fixing Tempest resources context to create network resources
[Verify] Fixing Tempest resources context to create network resources

Tempest resources context fails to create network resources because
Neutron raises the 'BadRequest: Invalid input for tenant_id. Reason:
'None' is not a valid string.' exception.
The issue was introduced by https://review.openstack.org/#/c/282918/.
So this patch is intended to fix the issue.

Closes-Bug: #1550848

Change-Id: I33b0bb2cdec55acf8446b0fab04e34c9f200fafd

eayunstack/rally,eayunstack/rally,openstack/rally,yeming233/rally,yeming233/rally,eonpatapon/rally,gluke77/rally,vganapath/rally,openstack/rally,vganapath/rally,vganapath/rally,vganapath/rally,eayunstack/rally,openstack/rally,gluke77/rally,gluke77/rally,gluke77/rally,openstack/rally,eonpatapon/rally