sphinx is now stricter

The documentation files often have minor typo or badly formatted
commands which makes sphinx emits a warning. To make sure we always
catch them via the Jenkins build, this patch makes sphinx to convert
warning to errors thus aborting the build, simply add to pass the -W
option to sphinx-build.

This patch also fix one warning:
* There is no source/_static dir so disable html_static_path

Test plan:

$ make clean; make html
rm -rf build/*
sphinx-build -b html -d build/doctrees  -W source build/html
Making output directory...
Running Sphinx v1.1.3
loading pickled environment... not yet created
building [html]: targets for 18 source files that are out of date
updating environment: 18 added, 0 changed, 0 removed
reading sources... [100%] zuul
looking for now-outdated files... none found
pickling environment... done
checking consistency... done
preparing documents... done
writing output... [100%] zuul
writing additional files... genindex py-modindex search
copying static files... done
dumping search index... done
dumping object inventory... done
build succeeded.

Build finished. The HTML pages are in build/html.
$

Change-Id: I55935fb5e869919ac639f841876aaf3871c71d17
Reviewed-on: https://review.openstack.org/16328
Reviewed-by: Paul Belanger <paul.belanger@polybeacon.com>
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins
Add ability to specify mavenName for maven jobs.

Previously maven jobs did not specify a maven name so which maven
install Jenkins treated as default was used for all JJB maven jobs. Add
the ability to set a maven install explicitly so that multiple maven
installs may be used.

Change-Id: I6a26635c31c5504b855063e1d4f6fa53132f26b5
Reviewed-on: https://review.openstack.org/19756
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins
Documentation fixes to make Sphinx happy

On this note, we have an issue with our current gate test for
documentation not properly catching these issues.  I'll be attempting to
address the issue in a future patch.

Change-Id: I7d0bea70ef98d1744200815ce12f1436729349e8
Signed-off-by: Paul Belanger <paul.belanger@polybeacon.com>
Reviewed-on: https://review.openstack.org/19889
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins