Initial replication setup.

This add replication setup through two new commands: ipa-replica-prepare
and ipa-replica-install. The procedure is to run ipa-replica-prepare
on an existing master. This will collect information about the realm
and the current master and create a file storing all of the information.
After copying that file to the new replica, ipa-replica-install is
run (with -r to create a read-only replica).

This version of the patch also includes fixes for the sasl mappings
on the replicas.

Remaining features:
- ssl for replication.
- automatic configuration of mesh topology for
  master (or a simpler way to replicate multiple
  masters.
- tool for view / configuring current replication.

ipa-python/ipautil.py

@@ -25,6 +25,7 @@ import logging
 import subprocess
 import os
 import stat
+import socket
 
 from string import lower
 import re
@@ -36,7 +37,6 @@ def realm_to_suffix(realm_name):
     terms = ["dc=" + x.lower() for x in s]
     return ",".join(terms)
 
-
 def template_str(txt, vars):
     return string.Template(txt).substitute(vars)