BUILD: Fix portability of NSS in file ipa_pwd.c

Tested-by: Timo Aaltonen <tjaalton@ubuntu.com>
Use private IPv4 addresses for tests

https://fedorahosted.org/freeipa/ticket/4139
Rename variables in test xmlrpc/dns_plugin

https://fedorahosted.org/freeipa/ticket/4139
Use reserved domain names for tests

https://fedorahosted.org/freeipa/ticket/4139