[DOC-24] Revert to Sphinx 1.5.3 for RTD

Change-Id: Ib70e11d11edf82a5d9ac1d7d8d34a7ee460684a2
Signed-off-by: Rich Bennett <rb2745@att.com>
diff --git a/docs/conf.py b/docs/conf.py
index 2ecd6d5..19b23f4 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -24,7 +24,7 @@
 # -- General configuration ------------------------------------------------
 
 # If your documentation needs a minimal Sphinx version, state it here.
-needs_sphinx = '1.6.3'
+needs_sphinx = '1.5.3'
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom