Move Redis code into fakeldap, since it's the only thing that still uses it.

Adjust auth unittests to skip fakeldap tests if Redis isn't around.
Adjust auth unittests to actually run the fakeldap tests if Redis /is/ around.

nova/auth/manager.py

@@ -201,7 +201,7 @@ class AuthManager(object):
 
     def __new__(cls, *args, **kwargs):
         """Returns the AuthManager singleton"""
-        if not cls._instance:
+        if not cls._instance or ('new' in kwargs and kwargs['new']):
             cls._instance = super(AuthManager, cls).__new__(cls)
         return cls._instance