[PATCH v1] doc: import sphinx rtd doc theme when available

[John McNamara <john.mcnamara@intel.com>]

The ReadTheDocs theme is no longer available by default in
Sphinx versions >= 1.3.1 and if it isn't available then an
exception is raised. This patch imports the ReadTheDocs
theme when it is available and warns but proceeds when it
isn't.

Signed-off-by: John McNamara <john.mcnamara@intel.com>
---
 doc/guides/conf.py | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/doc/guides/conf.py b/doc/guides/conf.py
index c3cd0bd..3988075 100644
--- a/doc/guides/conf.py
+++ b/doc/guides/conf.py
@@ -47,11 +47,17 @@
     # Python 3.
     import configparser
 
+try:
+    import sphinx_rtd_theme
 
-project = 'Data Plane Development Kit'
-
-if LooseVersion(sphinx_version) >= LooseVersion('1.3.1'):
     html_theme = "sphinx_rtd_theme"
+    html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
+except:
+    print('Install the sphinx ReadTheDocs theme for improved html documentation '
+          'layout: pip install sphinx_rtd_theme')
+    pass
+
+project = 'Data Plane Development Kit'
 html_logo = '../logo/DPDK_logo_vertical_rev_small.png'
 latex_logo = '../logo/DPDK_logo_horizontal_tag.png'
 html_add_permalinks = ""
-- 
2.7.4