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

Story: #2005924
Task: #34208

Change-Id: I2dee048b71e3758208fae438423cceae661c8f00

.zuul.yaml

@@ -223,16 +223,14 @@
       - integrated-gate-py3
       - openstack-lower-constraints-jobs
       - openstack-python-jobs
-      - openstack-python35-jobs
-      - openstack-python36-jobs
-      - openstack-python37-jobs
+      - openstack-python3-train-jobs
       - periodic-stable-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3
     check:
       jobs:
         - openstack-tox-functional
-        - openstack-tox-functional-py35
+        - openstack-tox-functional-py37
         - glance-eventlet-ssl-handshake-broken-py3:
             voting: false
         - glance-code-constants-check
@@ -265,7 +263,7 @@
     gate:
       jobs:
         - openstack-tox-functional
-        - openstack-tox-functional-py35
+        - openstack-tox-functional-py37
         - tempest-full:
             irrelevant-files: *tempest-irrelevant-files
         - neutron-grenade:

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 2.3.1
-envlist = py36,functional-py36,py35,functional-py35,py27,functional,pep8
+envlist = functional-py37,py37,py27,functional,pep8
 skipsdist = True
 
 [testenv]
@@ -31,10 +31,6 @@ passenv = *_proxy *_PROXY
 basepython = python2.7
 commands = stestr run --slowest {posargs}
 
-[testenv:py35]
-basepython = python3.5
-commands = stestr run --slowest {posargs}
-
 [testenv:py36]
 basepython = python3.6
 commands = stestr run --slowest {posargs}
@@ -51,16 +47,6 @@ ignore_errors = True
 commands =
   stestr run {posargs}
 
-[testenv:functional-py35]
-basepython = python3.5
-setenv =
-  TEST_PATH = ./glance/tests/functional
-ignore_errors = True
-whitelist_externals =
-  bash
-commands =
-  stestr run --blacklist-file ./broken-functional-py3-ssl-tests.txt {posargs}
-
 [testenv:functional-py36]
 basepython = python3.6
 setenv =