Update the UPPER_CONSTRAINTS_FILE to releases.openstack.org

1. Update the UPPER_CONSTRAINTS_FILE to releases.openstack.org[1]
2. Blacklist sphinx 2.1.0[2]

[1]: http://lists.openstack.org/pipermail/openstack-discuss/2019-May/006478.html
[2]: https://github.com/sphinx-doc/sphinx/issues/6440

Change-Id: Ie5f9ae1bd5c45617c6b7fde0e490d471e172c24e

doc/requirements.txt

@@ -8,4 +8,4 @@
 openstackdocstheme>=1.19.0 # Apache-2.0
 reno>=2.5.0 # Apache-2.0
 sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
-sphinx!=1.6.6,!=1.6.7,>=1.6.2;python_version>='3.4'  # BSD
+sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2;python_version>='3.4'  # BSD

tox.ini

@@ -8,7 +8,7 @@ usedevelop=True
 whitelist_externals = find
                       rm
 install_command = pip install {opts} {packages}
-deps = -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
+deps = -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
@@ -60,7 +60,7 @@ commands = bandit --skip B303 -r ansible kolla_ansible tests tools
 [testenv:venv]
 basepython = python3
 deps =
-  -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
+  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/test-requirements.txt
   -r{toxinidir}/doc/requirements.txt
 commands = {posargs}
@@ -68,7 +68,7 @@ commands = {posargs}
 [testenv:docs]
 basepython = python3
 deps =
-   -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
+   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
    -r{toxinidir}/requirements.txt
    -r{toxinidir}/doc/requirements.txt
 commands =
@@ -78,7 +78,7 @@ commands =
 [testenv:deploy-guide]
 basepython = python3
 deps =
-   -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
+   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
    -r{toxinidir}/requirements.txt
    -r{toxinidir}/doc/requirements.txt
 
@@ -95,7 +95,7 @@ commands =
 [testenv:releasenotes]
 basepython = python3
 deps =
-   -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
+   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
    -r{toxinidir}/requirements.txt
    -r{toxinidir}/doc/requirements.txt
 commands =