Introduce platform-specific adaptation for services used by FreeIPA.

Refactor FreeIPA code to allow abstracting all calls to external processes and
dependencies on modification of system-wide configuration. A platform provider
would give its own implementation of those methods and FreeIPA would use it
based on what's built in packaging process.

https://fedorahosted.org/freeipa/ticket/1605

ipapython/setup.py.in

@@ -65,7 +65,7 @@ def setup_package():
             classifiers=filter(None, CLASSIFIERS.split('\n')),
             platforms = ["Linux", "Solaris", "Unix"],
             package_dir = {'ipapython': ''},
-            packages = [ "ipapython" ],
+            packages = [ "ipapython", "ipapython.platform" ],
         )
     finally:
         del sys.path[0]