passx encode/decode functions

The string.encode('bz2') does not work in python3. Implement
passx_encode/passx_decode functions compatible with python 2.6, 2.7 and
3.3.

Add a simple unit test.

tests/test_conf.py

@@ -0,0 +1,32 @@
+from osc.conf import passx_encode, passx_decode
+from common import OscTestCase
+
+import os
+
+FIXTURES_DIR = os.path.join(os.getcwd(), 'conf_fixtures')
+
+def suite():
+    import unittest
+    return unittest.makeSuite(TestAddFiles)
+
+class TestConf(OscTestCase):
+    def _get_fixtures_dir(self):
+        return FIXTURES_DIR
+
+    def setUp(self):
+        return super(TestConf, self).setUp(copytree=False)
+    
+    def testPassxEncodeDecode(self):
+        
+        passwd = "J0e'sPassword!@#"
+        passx = passx_encode(passwd)
+        #base64.b64encode(passwd.encode('bz2'))
+        passx27 = "QlpoOTFBWSZTWaDg4dQAAAKfgCiAQABAEEAAJgCYgCAAMQAACEyYmTyei67AsYSDSaLuSKcKEhQcHDqA"
+        
+        self.assertEqual(passwd, passx_decode(passx))
+        self.assertEqual(passwd, passx_decode(passx27))
+        self.assertEqual(passx, passx27)
+
+if __name__ == '__main__':
+    import unittest
+    unittest.main()