gnu: Add python-configobj.

* gnu/packages/python.scm (python-configobj, python2-configobj): New
  variables.
* gnu/packages/patches/python-configobj-setuptools.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.

gnu/packages/patches/python-configobj-setuptools.patch

@@ -0,0 +1,30 @@
+From 16fbc38f13e435b4e3e1a37d706e64e05bad4691 Mon Sep 17 00:00:00 2001
+From: Leo Famulari <leo@famulari.name>
+Date: Tue, 10 Nov 2015 23:09:24 -0500
+Subject: [PATCH] patch build to use setuptools
+
+---
+ setup.py | 8 +++++++-
+ 1 file changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/setup.py b/setup.py
+index c6d57a6..27bf260 100644
+--- a/setup.py
++++ b/setup.py
+@@ -12,7 +12,12 @@
+ # http://opensource.org/licenses/BSD-3-Clause
+ import os
+ import sys
+-from distutils.core import setup
++
++try:
++    from setuptools import setup
++except ImportError:
++    from distutils.core import setup
++
+ # a simple import wouldn't work if we moved towards a package with __init__
+ from _version import __version__
+ 
+-- 
+2.6.2
+