Cleanup tox.ini
Cleanup tox.ini

Remove old and unused constraints environments.

this does not enable constraints (they were not enabled before) since
ironic-ui is not part of global requirements process.

Change-Id: I3f541f1e6322d229f0136f317cc14d83f2f75186

openstack/ironic-ui,openstack/ironic-ui,openstack/ironic-ui,openstack/ironic-ui