Updated from global requirements

Change-Id: I0caa7eb152b6f84ecb28ed333362ff3877a79679

test-requirements.txt

@@ -6,7 +6,7 @@ hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
 coverage!=4.4,>=4.0 # Apache-2.0
 mock>=2.0.0 # BSD
 python-subunit>=1.0.0 # Apache-2.0/BSD
-sphinx>=1.6.2 # BSD
+sphinx!=1.6.6,>=1.6.2 # BSD
 oslosphinx>=4.7.0 # Apache-2.0
 oslotest>=3.2.0 # Apache-2.0
 testrepository>=0.0.18 # Apache-2.0/BSD