Update TOX_CONSTRAINTS_FILE for stable/xena

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/xena branch, tests will
continue to use the upper-constraints list on master.

Change-Id: Ib7f0d3047e4713b805d9ce78bc53db34cfdf5776

.gitreview

@@ -2,3 +2,4 @@
 host=review.opendev.org
 port=29418
 project=openstack/python-tackerclient.git
+defaultbranch=stable/xena

.zuul.yaml

@@ -1,7 +1,6 @@
 - project:
     templates:
       - check-requirements
-      - openstack-lower-constraints-jobs
       - openstack-python3-xena-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3

lower-constraints.txt

@@ -1,56 +0,0 @@
-appdirs==1.3.0
-Babel==2.3.4
-cliff==2.8.0
-cmd2==0.8.0
-coverage==4.0
-ddt==1.0.1
-debtcollector==1.2.0
-decorator==3.4.0
-deprecation==1.0
-dogpile.cache==0.6.2
-extras==1.0.0
-fixtures==3.0.0
-iso8601==0.1.11
-jmespath==0.9.0
-jsonpatch==1.16
-jsonpointer==1.13
-keystoneauth1==3.4.0
-linecache2==1.0.0
-monotonic==0.6
-msgpack-python==0.4.0
-munch==2.1.0
-netaddr==0.7.18
-netifaces==0.10.4
-openstacksdk==0.11.2
-os-client-config==1.28.0
-os-service-types==1.2.0
-osc-lib==1.8.0
-oslo.config==5.2.0
-oslo.context==2.19.2
-oslo.i18n==3.15.3
-oslo.log==3.36.0
-oslo.serialization==2.18.0
-oslo.utils==3.40.0
-pbr==2.0.0
-positional==1.2.1
-prettytable==0.7.2
-pyinotify==0.9.6
-pyparsing==2.1.0
-pyperclip==1.5.27
-python-dateutil==2.5.3
-python-keystoneclient==3.8.0
-python-mimeparse==1.6.0
-python-subunit==1.0.0
-pytz==2013.6
-PyYAML==3.12
-requests==2.14.2
-requests-mock==1.2.0
-requestsexceptions==1.2.0
-rfc3986==0.3.1
-simplejson==3.5.1
-stestr==2.0.0
-stevedore==1.20.0
-testtools==2.2.0
-traceback2==1.4.0
-unittest2==1.1.0
-wrapt==1.7.0

tox.ini

@@ -12,7 +12,7 @@ setenv = VIRTUAL_ENV={envdir}
          LC_ALL=C
 usedevelop = True
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/xena}
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/test-requirements.txt
 commands = stestr run --slowest {posargs}
@@ -30,7 +30,7 @@ commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:releasenotes]
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/xena}
   -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
@@ -52,9 +52,3 @@ exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,tools
 # F821 undefined name 'unicode'
 # if isinstance(config, str) or isinstance(config, unicode):
 builtins = unicode
-
-[testenv:lower-constraints]
-deps =
-  -c{toxinidir}/lower-constraints.txt
-  -r{toxinidir}/test-requirements.txt
-  -r{toxinidir}/requirements.txt