Use NSS for name->resolution in IPA installer
This fixes scenarios where IPA server is not able to resolve own name
and option --ip-address was not specified by the user.
This partially reverts changes from commit
dc405005f537cf278fd6ddfe6b87060bd13d9a67
https://fedorahosted.org/freeipa/ticket/5962
Reviewed-By: Martin Basti <mbasti@redhat.com>