Enforce python3 support in Anchor
Enforce python3 support in Anchor

Anchor supports py34 environment since commit cc98c34. New commits
should be checked against python3.

Change-Id: Iadf71aaae342dace42abb7d94dfc42eff97763ea

openstack-infra/project-config,noorul/os-project-config,dongwenjuan/project-config,dongwenjuan/project-config,coolsvap/project-config,openstack-infra/project-config,Tesora/tesora-project-config,Tesora/tesora-project-config,noorul/os-project-config,coolsvap/project-config