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

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

Masakari 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

Co-authored-by: Ghanshyam <gmann@ghanshyammann.com>
Change-Id: If7ba4697a2e5e7f6390187e094a1e7f3c1996078

.zuul.yaml

@@ -40,7 +40,6 @@
     templates:
       - check-requirements
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
       - openstack-python3-ussuri-jobs
       - publish-openstack-docs-pti
     check:

releasenotes/notes/drop-py-2-7-a4b96d486289a772.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. Last release of ec2-api
+    to support python 2.7 is OpenStack Train. The minimum version of Python now
+    supported by ec2-api is Python 3.6.

setup.cfg

@@ -14,8 +14,6 @@ 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

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 3.1
-envlist = pep8,py27,py37,docs,api-ref
+envlist = pep8,py37,docs,api-ref
 skipsdist = True
 ignore_basepython_conflict = True