Allows installation as root user

* Allows root to install OpenCafe. This is necessary for running
  OpenCafe in Docker

Change-Id: Ia56ca03d156c4dfbde06087568517e8e7dfd7a4f

cafe/configurator/managers.py

@@ -45,10 +45,9 @@ class PlatformManager(object):
         effective_user = os.getenv("USER")
 
         if not cls.USING_WINDOWS and not cls.USING_VIRTUALENV:
-            if effective_user == 'root' and real_user != 'root':
+            if effective_user == 'root' and real_user not in ['root', None]:
                 # Running 'sudo'.
                 return real_user
-
         elif cls.USING_WINDOWS:
             return getpass.getuser()