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

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

monasca-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

Depends-On: https://review.opendev.org/#/c/693631/
Change-Id: I47be69fe3b53df70ba775bad342d88129de5ff0a

.zuul.yaml

@@ -4,5 +4,4 @@
       - horizon-non-primary-django-jobs
       - openstack-cover-jobs-horizon
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs-horizon
       - openstack-python3-ussuri-jobs-horizon

README.rst

@@ -145,4 +145,4 @@ directory of this project:
 
 ::
 
-   $ tox -e py27,py36
+   $ tox -e py36

releasenotes/notes/drop-py-2-7-4bed1d8bdb530b1d.yaml

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

setup.cfg

@@ -12,8 +12,6 @@ classifier =
     License :: OSI Approved :: Apache Software License
     Operating System :: POSIX :: Linux
     Programming Language :: Python
-    Programming Language :: Python :: 2
-    Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7

test-requirements.txt

@@ -6,10 +6,8 @@ hacking>=1.1.0,<1.2.0 # Apache-2.0
 
 coverage!=4.4,>=4.0 # Apache-2.0
 mock>=2.0.0 # BSD
-funcsigs>=1.0.0;python_version=='2.7' or python_version=='2.6' # Apache-2.0
 nodeenv>=0.9.4 # BSD
 selenium>=2.50.1 # Apache-2.0
 # Docs Requirements
-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

tox.ini

@@ -1,9 +1,10 @@
 [tox]
-envlist = py27,py37,py3-{dj111,dj22},pep8
+envlist = py37,py3-{dj111,dj22},pep8
 minversion = 2.6
 skipsdist = True
 
 [testenv]
+basepython = python3
 usedevelop = True
 passenv =  http_proxy
            HTTP_PROXY
@@ -25,21 +26,14 @@ commands =
     find . -type f -name "*.pyc" -delete
     /bin/bash run_tests.sh -N {posargs}
 
-[testenv:py27]
-setenv =
-   DJANGO_SETTINGS_MODULE=monitoring.test.settings
-
 [testenv:pep8]
-basepython = python3
 commands =
   /bin/bash run_tests.sh -N --pep8
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:cover]
-basepython = python3
 commands = /bin/bash run_tests.sh -N --coverage {posargs}
 
 [flake8]
@@ -51,7 +45,6 @@ builtins = _
 exclude = .venv,.git,.tox,dist,*lib/python*,*egg,build,panel_template,dash_template,local_settings.py,*/local/*,*/test/test_plugins/*
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt