Add py3.5 support in setup.cfg

As defined in https://governance.openstack.org/tc/goals/pike/python35.html
Pike community goal for py35, adding py35 to setup.cfg.

I believe the py35 unit tests should be enough for this, but eventually we
should setup a py35 dsvm test as well.

Change-Id: I44d5465bf4d6223e603853c03d53d2b8cd98d1e0
diff --git a/setup.cfg b/setup.cfg
index a8732dc..09b71eb 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -18,6 +18,7 @@
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.3
     Programming Language :: Python :: 3.4
+    Programming Language :: Python :: 3.5
 
 [files]
 packages =