[ussuri][goal] Drop python 2.7 support and testing

OpenStack is dropping the py2.7 support in ussuri cycle.

freezer-web-ui is ready with python 3 and ok to drop the
python 2.7 support.

Complete discussion & schedule can be found in
- http://lists.openstack.org/pipermail/openstack-discuss/2019-October/010142.html
- https://etherpad.openstack.org/p/drop-python2-support

Ussuri Communtiy-wide goal:
https://governance.openstack.org/tc/goals/selected/ussuri/drop-py27.html

Change-Id: I7a85a88ad3d248ea081eb22db6507f9bd21493f7

.zuul.yaml

@@ -3,9 +3,7 @@
       - check-requirements
       - horizon-non-primary-django-jobs
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
+      - openstack-python3-ussuri-jobs
-      - openstack-python35-jobs
-      - openstack-python36-jobs
     check:
       jobs:
         - freezer-web-ui-ubuntu

doc/requirements.txt

@@ -2,7 +2,6 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-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
 sphinxcontrib-apidoc>=0.2.0  # BSD
 openstackdocstheme>=1.18.1 # Apache-2.0

releasenotes/notes/drop-py-2-7-5fbb19deece255ca.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. Last release of freezer-web-ui
+    to support py2.7 is OpenStack Train. The minimum version of Python now
+    supported by freezer-web-ui is Python 3.6.

setup.cfg

@@ -17,9 +17,9 @@ classifier =
     Operating System :: OS Independent
     Operating System :: POSIX :: Linux
     Programming Language :: Python
-    Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.5
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
     Topic :: Internet :: WWW/HTTP
 keywords =
     horizon

test-requirements.txt

@@ -11,7 +11,6 @@ oslo.config>=5.2.0 # Apache-2.0
 testrepository>=0.0.18 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT
 unittest2>=1.1.0 # BSD
-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
 oslosphinx>=4.7.0 # Apache-2.0
 astroid==1.6.5;python_version<"3.0" # LGPLv2.1

tox.ini

@@ -1,9 +1,10 @@
 [tox]
-envlist = py27,py36,py37,py3-{dj111,dj22},pep8,pylint,docs
+envlist = py36,py37,py3-{dj111,dj22},pep8,pylint,docs
 minversion = 2.0
 skipsdist = True
 
 [testenv]
+basepython = python3
 usedevelop = True
 setenv = VIRTUAL_ENV={envdir}
          NOSE_WITH_OPENSTACK=1
@@ -19,9 +20,6 @@ commands =
    dj22: pip install django>=2.2,<2.3
    python manage.py test {posargs}
 
-[testenv:py27]
-basepython = python2.7
-
 [testenv:py36]
 basepython = python3.6
 
@@ -29,19 +27,15 @@ basepython = python3.6
 basepython = python3.7
 
 [testenv:pep8]
-basepython = python3
 commands = flake8 {posargs}
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:cover]
-basepython = python3
 commands = python setup.py test --coverage --testr-args={posargs}
 
 [testenv:docs]
-basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 setenv = DJANGO_SETTINGS_MODULE=disaster_recovery.test.settings
 commands = python setup.py build_sphinx
@@ -55,7 +49,6 @@ max-complexity = 20
 ignore = H405,H404,H403,H401,H238,H306,H701
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt