Remove pbr warnerrors in favor of sphinx check

This change removes the now unused "warnerrors" setting,
which is replaced by "warning-is-error" in sphinx
releases >= 1.5 [1].

[1] http://lists.openstack.org/pipermail/openstack-dev/
2017-March/113085.html

Change-Id: I05b19288a444d346cebe83a9aa0422d8655f6f0c

ironic_inspector/node_cache.py

@@ -340,9 +340,10 @@ class NodeInfo(object):
 
         :param ports: List of ports with all their attributes
                       e.g  [{'mac': xx, 'ip': xx, 'client_id': None},
-                            {'mac': xx, 'ip': None, 'client_id': None}]
+                      {'mac': xx, 'ip': None, 'client_id': None}]
                       It also support the old style of list of macs.
-        A warning is issued if port already exists on a node.
+                      A warning is issued if port already exists on a node.
+
         :param ironic: Ironic client to use instead of self.ironic
         """
         existing_macs = []

setup.cfg

@@ -88,9 +88,9 @@ output_file = ironic_inspector/locale/ironic_inspector.pot
 all_files = 1
 build-dir = doc/build
 source-dir = doc/source
+warning-is-error = 1
 
 [pbr]
-warnerrors = True
 autodoc_index_modules = True
 autodoc_exclude_modules =
     ironic_inspector.migrations.*