Use upper-constraints in tox test environments
Use upper-constraints in tox test environments

Recently OpenStack introduced a mechanism to specify a constrained
"working set" of packages that are "guaranteed" to produce a working
OpenStack environment. This pinning of packages limits the more
broadly-defined requirements.txt which is managed by
global-requirements.

This patch modifies our tox test environment to use upper-constraints
and explictly removes those requirements from the "venv" tox
environment that is used by some commands in infra.

Change-Id: I84582370e139fc5812bc85ae5341f7f9c8b93ff5
Closes-Bug: 1554791

openstack/horizon,bac/horizon,openstack/horizon,BiznetGIO/horizon,sandvine/horizon,BiznetGIO/horizon,bac/horizon,ChameleonCloud/horizon,sandvine/horizon,wolverineav/horizon,BiznetGIO/horizon,sandvine/horizon,coreycb/horizon,ChameleonCloud/horizon,ChameleonCloud/horizon,noironetworks/horizon,yeming233/horizon,bac/horizon,wolverineav/horizon,yeming233/horizon,coreycb/horizon,noironetworks/horizon,openstack/horizon,wolverineav/horizon,NeCTAR-RC/horizon,coreycb/horizon,BiznetGIO/horizon,yeming233/horizon,wolverineav/horizon,NeCTAR-RC/horizon,noironetworks/horizon,NeCTAR-RC/horizon,yeming233/horizon,noironetworks/horizon,openstack/horizon,NeCTAR-RC/horizon,ChameleonCloud/horizon,bac/horizon,sandvine/horizon,coreycb/horizon