Update TOX_CONSTRAINTS_FILE for stable/victoria

Update the URL to the upper-constraints file to point to the redirect
rule on releases.openstack.org so that anyone working on this branch
will switch to the correct upper-constraints list automatically when
the requirements repository branches.

Until the requirements repository has as stable/victoria branch, tests will
continue to use the upper-constraints list on master.

Change-Id: I744620a54e89eba4db491eb25a66a231bfc85f03

tox.ini

@@ -9,7 +9,7 @@ basepython = python3
 setenv = VIRTUAL_ENV={envdir}
 usedevelop = True
 deps =
-       -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+       -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/victoria}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands = find . -type f -name "*.py[c|o]" -delete
@@ -44,7 +44,7 @@ commands =
 
 [testenv:docs]
 deps =
-       -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+       -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/victoria}
        -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html
 
@@ -59,7 +59,7 @@ import_exceptions = heatclient._i18n
 
 [testenv:releasenotes]
 deps =
-       -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+       -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/victoria}
        -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html