Enable doc8 style checker for *.rst files

This patch is enabling the doc8 style checker for the *.rst files in
Ironic.

Since this patch is just the first stab at enabling this new check two
errors are currently being ignored by doc8 because of the number of
occurrences in our docs:

* D000 - Duplicated target names. We do have many links with generic
         names scattered around the docs (e.g "see", "link")

* D001 - Line's too long

These errors will be fixed in a following patch.

Change-Id: I32fb5a3104b9773c55a80a84dd81e49c567c76ac

doc/source/dev/contributing.rst

@@ -48,7 +48,7 @@ Bug tracker
 
 Mailing list (prefix subjects with ``[ironic]`` for faster responses)
     http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
-    
+
 Wiki
     http://wiki.openstack.org/Ironic
 

doc/source/drivers/amt.rst

@@ -61,16 +61,14 @@ A detailed reference is available here, and a short guide follows below:
   * Ubuntu: ``python-openwsman``'s most recent version is 2.4.3 which
     is enough.
 
-  * Or build it yourself from::
-
-    https://github.com/Openwsman/openwsman
+  * Or build it yourself from: https://github.com/Openwsman/openwsman
 
 * Enable the ``pxe_amt`` or ``agent_amt`` driver by adding it to the
   configuration option ``enabled_drivers`` (typically located at
   ``/etc/ironic/ironic.conf``) and restart the ``ironic-conductor``
   process::
 
-  service ironic-conductor restart
+    service ironic-conductor restart
 
 * Enroll an AMT node
 

doc/source/drivers/oneview.rst

@@ -126,7 +126,7 @@ Overview
 ``agent_pxe_oneview`` driver uses PXEBoot for boot and AgentDeploy for deploy.
 
 Configuring and enabling the driver
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 1. Add ``agent_pxe_oneview`` to the list of ``enabled_drivers`` in
    ``/etc/ironic/ironic.conf``. For example::

test-requirements.txt

@@ -3,6 +3,7 @@
 # process, which may cause wedges in the gate later.
 hacking<0.11,>=0.10.0
 coverage>=3.6 # Apache-2.0
+doc8 # Apache-2.0
 fixtures>=1.3.1 # Apache-2.0/BSD
 mock>=1.2 # BSD
 Babel>=1.3 # BSD

tox.ini

@@ -31,6 +31,8 @@ commands =
   {toxinidir}/tools/run_bashate.sh {toxinidir}/devstack
   # Check that .po and .pot files are valid:
   bash -c "find ironic -type f -regex '.*\.pot?' -print0|xargs -0 -n 1 msgfmt --check-format -o /dev/null"
+  # Check the *.rst files
+  doc8 README.rst CONTRIBUTING.rst doc/source --ignore D001 --ignore D000
 
 [testenv:cover]
 setenv = VIRTUAL_ENV={envdir}