doc: light cleanup of the ironic-integration page

Remove the commands required to configure the nodes, the resources
and the flavors and refer to the Ironic documentation instead.

This change also removes the only reference in Sahara to the
old pxe_ipmitool driver, which is going to be removed:
http://lists.openstack.org/pipermail/openstack-dev/2018-March/128438.html

Remove also the reference to a bug which was fixed for a (long) while.

Change-Id: I5366298f82afb928b7c7520e2eb815d3ff597885

doc/source/user/sahara-on-ironic.rst

@@ -45,48 +45,13 @@ from the bare metal performance with self-service resource provisioning.
 
 - Add bare metal servers to your environment manually referencing their
   IPMI addresses (Ironic does not detect servers), for Ironic to manage
-  the servers power and network. For example:
+  the servers power and network. Also, configure the scheduling
+  information and add the required flavors. Please check the
+  :ironic-doc:`Enrollment section of the Ironic installation guide
+  <install/enrollment.html>`.
 
-.. code-block:: bash
 
-   $ ironic node-create -d pxe_ipmitool \
-     -i ipmi_address=$IP_ADDRESS \
-     -i ipmi_username=$USERNAME \
-     -i ipmi_password=$PASSWORD \
-     -i pxe_deploy_kernel=$deploy.kernel.id \
-     -i pxe_deploy_ramdisk=$deploy.ramfs.id
-
-   $ ironic port-create -n $NODE_ID -a "$MAC_eth1"
-..
-
-- Add the hardware information:
-
-.. code-block:: bash
-
-   $ ironic node-update $NODE_ID add properties/cpus=$CPU \
-     properties/memory_mb=$RAM properties/local_gb=$ROOT_GB \
-     properties/cpu_arch='x86_64'
-..
-
-7. Add a special flavor for the bare metal instances with an arch meta
-   parameter to match the virtual architecture of the server's CPU
-   with the metal one. For example:
-
-.. code-block:: bash
-
-   $ nova flavor-create baremetal auto $RAM $DISK_GB $CPU
-   $ nova flavor-key baremetal set cpu_arch=x86_64
-..
-
-Note:
-+++++
-The vCPU ad vRAM parameters (x86_64 in the example) will not be applied because
-the operating system has access to the real CPU cores and RAM. Only the root
-disk parameter is applied, and Ironic will resize the root disk partition.
-Ironic supports only a flat network topology for the bare metal provisioning,
-you must use Neutron to configure it.
-
-8. Launch your Sahara cluster on Ironic from the cluster template:
+7. Launch your Sahara cluster on Ironic from the cluster template:
 
    * Log in to Horizon.
 
@@ -111,9 +76,6 @@ Known limitations:
 ------------------
 
 * Security groups are not applied.
-* When booting a nova instance with a bare metal flavor, the user can not
-  provide a pre-created neutron port to ``nova boot`` command. `LP1544195
-  <https://bugs.launchpad.net/nova/+bug/1544195>`_
 * Nodes are not isolated by projects.
 * VM to Bare Metal network routing is not allowed.
 * The user has to specify the count of ironic nodes before Devstack deploys