Switch to Python unittest

Nose has some inherent problems as it is file-based, so let's switch
to the Python default anyway.

Signed-off-by: martin f. krafft <madduck@madduck.net>
diff --git a/setup.py b/setup.py
index 4dd88a4..ebcc4ff 100644
--- a/setup.py
+++ b/setup.py
@@ -26,6 +26,5 @@
             'reclass-ansible = reclass.adapters.ansible:cli'
         ]
     },
-    install_requires = ['pyyaml'],
-    setup_requires = ['nose'],
+    install_requires = ['pyyaml']
 )