Replace ipaplatform's symlinks with a meta importer

Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Petr Spacek <pspacek@redhat.com>

ipaplatform/__init__.py.in

@@ -1,12 +1,20 @@
 #
 # Copyright (C) 2015  FreeIPA Contributors see COPYING for license
 #
+"""Module containing platform-specific functionality.
+
+ipaplatform.constants
+ipaplatform.paths
+ipaplatform.services
+ipaplatform.tasks
+"""
+import os
 
-'''
-Module containing platform-specific functionality for every platform.
-'''
 
 NAME = "__PLATFORM__"
 
-# FIXME: too much cyclic dependencies
-# from __PLATFORM__ import paths, tasks, services
+# Create an alias for platform specific modulues, e.g.
+# 'import ipaplatform.paths' loads 'ipaplatform/NAME/paths.py'.
+
+__path__.append(
+    os.path.join(os.path.dirname(os.path.abspath(__file__)), NAME))

ipaplatform/base/services.py

@@ -483,7 +483,10 @@ class SystemdService(PlatformService):
 
 # Objects below are expected to be exported by platform module
 
-service = None
+def base_service_class_factory(name):
+    raise NotImplementedError
+
+service = base_service_class_factory
 knownservices = None
 
 # System may support more time&date services. FreeIPA supports ntpd only, other