Fix setup.py to work with pip 6.x

The parse_requirements function has changed, and requires a session
parameter to be supplied. See this for an example of the complaint and a
fix.

jmcarp/robobrowser#32

setup.py

@@ -1,4 +1,5 @@
 import os
+import uuid
 from setuptools import setup
 from pip.req import parse_requirements
 
@@ -35,6 +36,6 @@ def read(fname):
             "rabbitmq = ceilometer_publisher_rabbitmq.queue:QueuePublisher",
         ],
     },
-    install_requires=[str(req.req) for req in parse_requirements("requirements.txt")],
+    install_requires=[str(req.req) for req in parse_requirements("requirements.txt", session=uuid.uuid1())],
     include_package_data=True
 )