Fix unit tests in python3

Fix the check_output in unit tests, the result was being
intrepid as a byte string which caused unit tests to fail.
This patch makes it a utf-8 string.

Change-Id: Iba5c50762846ef5266eddd397aca44b01d411354
Signed-off-by: Chuck Short <chucks@redhat.com>

tests/base.py

@@ -38,7 +38,7 @@ class ScriptTestBase(base.BaseTestCase):
         try:
             return subprocess.check_output(cmd,
                                            stderr=subprocess.STDOUT,
-                                           env=self.env)
+                                           env=self.env).decode('utf-8')
         # NOTE(bnemec): If we don't handle this exception, all we get is the
         # exit code if the command fails.
         except subprocess.CalledProcessError as e: