Updated from global requirements

Change-Id: I0aedf0e3b98de0d44cb7b32c9ccd72ecd1e0003c
diff --git a/doc/requirements.txt b/doc/requirements.txt
index 597b54e..d959d44 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -3,4 +3,4 @@
 # process, which may cause wedges in the gate later.
 openstackdocstheme>=1.18.1 # Apache-2.0
 reno>=2.5.0 # Apache-2.0
-sphinx!=1.6.6,>=1.6.2 # BSD
+sphinx!=1.6.6,!=1.6.7,>=1.6.2 # BSD