turn on warning-is-error for sphinx

Update a docstring that had an rst formatting error and then turn on the
warning-is-error flag to prevent future issues with documentation.

Change-Id: I29fc90a2eb1599c9da88489415a9e080d88cc707
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

osc_lib/api/api.py

@@ -28,10 +28,13 @@ class BaseAPI(object):
 
     Encapsulate the translation between keystoneauth1.session.Session
     and requests.Session in a single layer:
+
     * Restore some requests.session.Session compatibility;
       keystoneauth1.session.Session.request() has the method and url
       arguments swapped from the rest of the requests-using world.
-    * Provide basic endpoint handling when a Service Catalog is not available.
+    * Provide basic endpoint handling when a Service Catalog is not
+      available.
+
     """
 
     # Which service are we? Set in API-specific subclasses

setup.cfg

@@ -26,7 +26,7 @@ packages =
 source-dir = doc/source
 build-dir = doc/build
 all_files = 1
-#warning-is-error = 1
+warning-is-error = 1
 
 [pbr]
 autodoc_index_modules = True