Updating ironic configurations in nova.conf

Irnoic configurations in nova compute node have been changed with
respect to the master code of ironic and nova. admin_url
configuration is with v3 version but other details are with
respect to v2.0 version of keystone authentication.
Updated scheduler_host_manager, compute_driver and admin_url
values in the nova.conf template to support ironic master
branch code.

Change-Id: I78bee3fdf082bcd526507b479be3afaee80ba899
Closes-Bug: #1619211