Fix README extension

This is restructured text.

setup.py

@@ -18,7 +18,7 @@ setup(
         + '\n' +
         read('CHANGELOG.rst')
         + '\n' +
-        read('slapos', 'recipe', 'cmmi', 'README.txt')
+        read('slapos', 'recipe', 'cmmi', 'README.rst')
         + '\n' +
         'Download\n'
         '========\n'

slapos/recipe/cmmi/tests.py

@@ -321,7 +321,7 @@ class NonInformativeTests(unittest.TestCase):
 def test_suite():
     suite = unittest.TestSuite((
         doctest.DocFileSuite(
-            'README.txt',
+            'README.rst',
             setUp=setUp,
             tearDown=zc.buildout.testing.buildoutTearDown,
             optionflags=optionflags,