Moving unittest2 into conditional requires

Unittest2 is only needed for py26 and under. As we want to eventually
be able to make OpenCAFE Python 3 compatible, we need to keep back-
compatiblity requirements on a conditional level.

Change-Id: Id7fc4ede4c1aef84759e72be0fac28c86b1a09bc

pip-requires

@@ -1,6 +1,5 @@
 decorator
 paramiko
-unittest2==0.5.1
 
 # Keep this turned off unless your using the rsyslog client
 # i.e. you know what you're doing :)

setup.py

@@ -62,7 +62,8 @@ requires = open('pip-requires').readlines()
 
 # Add additional requires for Python 2.6 support
 if sys.version_info < (2, 7):
-    requires.append('argparse==1.2.1')
+    oldpy_requires = ['argparse>=1.2.1', 'unittest2>=0.5.1']
+    requires.extend(oldpy_requires)
 
 
 #cmdclass hook allows setup to make post install call