Update tox for OpenStack

requestsexceptions is now part of the shade project, so update
adminstrivia things. We should declare 3.5 support, and not 3.4 or 3.3,
since they're untested. We should also remove the infra exclusions since
it's no longer under that umbrella (also, no code changes were required)

Change-Id: Idc1a5449c6ed5a790083a63dfbd5815fbc9dd650

setup.cfg

@@ -16,8 +16,7 @@ classifier =
     Programming Language :: Python :: 2
     Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.3
-    Programming Language :: Python :: 3.4
+    Programming Language :: Python :: 3.5
 
 [files]
 packages =

test-requirements.txt

@@ -1 +1 @@
-flake8>=2.2.4,<=2.4.1
+hacking>=0.12.0,!=0.13.0,<0.14  # Apache-2.0

tox.ini

@@ -1,7 +1,7 @@
 [tox]
 minversion = 1.6
 skipsdist = True
-envlist = pep8, py27
+envlist = pep8, py27, py35
 
 [testenv]
 usedevelop = True
@@ -25,8 +25,5 @@ commands = python setup.py build_sphinx
 commands = {posargs}
 
 [flake8]
-# These are ignored intentionally in openstack-infra projects;
-# please don't submit patches that solely correct them or enable them.
-ignore = E125,E129,H
 show-source = True
 exclude = .venv,.tox,dist,doc,build,*.egg