Dropping the py35 testing

All the integration testing has been moved to
Bionic now[1] and py3.5 is not tested runtime for
Train or stable/stein[2].

As per below ML thread, we are good to drop the py35
testing now:
http://lists.openstack.org/pipermail/openstack-discuss/2019-April/005097.html

[1] http://lists.openstack.org/pipermail/openstack-discuss/2019-April/004647.html
[2]
https://governance.openstack.org/tc/reference/runtimes/stein.html
https://governance.openstack.org/tc/reference/runtimes/train.html

Change-Id: I52a390177356da2e79aac8789a9ef96d57043149

.zuul.yaml

@@ -3,7 +3,6 @@
       - check-requirements
       - openstack-lower-constraints-jobs
       - openstack-python-jobs
-      - openstack-python35-jobs
       - openstack-python36-jobs
       - openstack-python37-jobs
       - release-notes-jobs-python3

setup.cfg

@@ -15,7 +15,7 @@ classifier =
     Programming Language :: Python :: 2
     Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.5
+    Programming Language :: Python :: 3.6
     Development Status :: 5 - Production/Stable
     Natural Language :: English
     Intended Audience :: Developers

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 2.0
-envlist = py27,py35,py36,pep8,pylint
+envlist = py27,py36,pep8,pylint
 skipsdist = True
 
 [testenv]
@@ -34,17 +34,6 @@ commands =
     rm -f .coverage
     rm -rf .testrepository
 
-[testenv:py35]
-basepython = python3.5
-setenv = OS_PATH_TEST = ./freezer_api/tests/unit
-commands =
-    find . -type f -name "*.py[c|o]" -delete
-    rm -rf .testrepository
-    python setup.py test --coverage --coverage-package-name freezer_api --testr-args={posargs}
-    coverage report -m
-    rm -f .coverage
-    rm -rf .testrepository
-
 [testenv:py36]
 basepython = python3.6
 setenv = OS_PATH_TEST = ./freezer_api/tests/unit