Docs: Troubleshooting info for 3.13 kernel upgrade

Add a note to the OSA Operations Guide about the need to re-run the
hosts setup playbook after a kernel upgrade from v3.13. This patch also
incidentally moves the introductory section text to be above the TOC.

Change-Id: Ia04cec6c689d02bff98a6adb623914703b9e3f7b
Closes-Bug: 1579963

doc/source/install-guide/ops-troubleshooting.rst

@@ -4,6 +4,19 @@
 Troubleshooting
 ===============
 
+Host kernel upgrade from version 3.13
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Ubuntu kernel packages newer than version 3.13 contain a change in
+module naming from ``nf_conntrack`` to ``br_netfilter``. After
+upgrading the kernel, re-run the ``openstack-hosts-setup.yml``
+playbook against those hosts. See `OSA bug 157996`_ for more
+information.
+
+.. _OSA bug 157996: https://bugs.launchpad.net/openstack-ansible/+bug/1579963
+
+
+
 Container networking issues
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -77,7 +90,7 @@ Examples of the information gathered are:
     * Linux distribution
     * Kernel version
     * Network interfaces
-    
+
 To improve performance, particularly in large deployments, you can
 cache host facts and information.
 

doc/source/install-guide/ops.rst

@@ -4,6 +4,9 @@
 Chapter 8. Operations
 =====================
 
+The following operations and troubleshooting procedures apply to
+installed environments.
+
 .. toctree::
 
    ops-addcomputehost.rst
@@ -12,9 +15,6 @@ Chapter 8. Operations
    ops-troubleshooting.rst
 
 
-The following operations apply to environments after initial
-installation.
-
 --------------
 
 .. include:: navigation.txt