Update tox.ini files to use stein constraints

This updates the upper-constraints.txt used by tox for
installing python modules to reference the stable/stein
constraints.

Change-Id: If3880fba415ce3023e497ff557efae1b2b65ccff
Partial-Bug: 1834216
Signed-off-by: Don Penney <don.penney@windriver.com>

nfv/tox.ini

@@ -16,7 +16,9 @@ stxdir = {toxinidir}/../..
 
 [testenv]
 recreate = True
-install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/upper-constraints.txt} {opts} {packages}
+install_command = pip install \
+    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/stable/stein/upper-constraints.txt} \
+    {opts} {packages}
 whitelist_externals = cp
 
 [nfv]

nova-api-proxy/tox.ini

@@ -5,7 +5,9 @@ skipsdist = True
 
 [testenv]
 basepython = python3
-install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt?h=stable/pike}  {opts} {packages}
+install_command = pip install \
+    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/stable/stein/upper-constraints.txt} \
+    {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
          OS_STDOUT_CAPTURE=1
          OS_STDERR_CAPTURE=1