Fix pep8 errors

Recent pep8 upgrade and corresponding pycodestyle update break
pep8 job due to the new rules.
- E402 module level import not at top of file
- E731 do not assign a lambda expression, use a def
- W503 line break before binary operator

Change-Id: I40d386b44489e6847dd9c441b3feb56e099d252e

api-ref/source/conf.py

@@ -25,6 +25,8 @@
 import os
 import sys
 
+from neutron_lib.version import version_info
+
 extensions = [
     'os_api_ref',
     'openstackdocstheme',
@@ -70,7 +72,6 @@ bug_tag = 'api-ref'
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
-from neutron_lib.version import version_info
 # The full version, including alpha/beta/rc tags.
 release = version_info.release_string()
 # The short X.Y version.

neutron_lib/api/validators/__init__.py

@@ -1013,8 +1013,8 @@ def validate_subports(data, valid_values=None):
         if segmentation_type == 'inherit':
             return
         segmentation_id = subport.get("segmentation_id")
-        if ((not segmentation_type or segmentation_id is None)
-                and len(subport) > 1):
+        if ((not segmentation_type or segmentation_id is None) and
+                len(subport) > 1):
             msg = _("Invalid subport details '%s': missing segmentation "
                     "information. Must specify both segmentation_id and "
                     "segmentation_type") % subport

neutron_lib/tests/unit/api/definitions/base.py

@@ -104,8 +104,8 @@ class DefinitionBaseTestCase(test_base.BaseTestCase):
             self.skipTest('API definition is not related to standardattr.')
 
     def test_resource_map(self):
-        if (not self.resource_map and not self.subresource_map
-                and not self.is_shim_extension):
+        if (not self.resource_map and not self.subresource_map and
+                not self.is_shim_extension):
             self.fail('Missing resource and subresource map, '
                       'what is this extension doing?')
         elif self.is_shim_extension:

neutron_lib/tests/unit/callbacks/test_manager.py

@@ -115,7 +115,9 @@ class CallBacksManagerTestCase(base.BaseTestCase):
                 [resources.PORT][events.BEFORE_CREATE][0][1]))
 
     def test_unsubscribe_during_iteration(self):
-        unsub = lambda r, e, *a, **k: self.manager.unsubscribe(unsub, r, e)
+        def unsub(r, e, *a, **k):
+            return self.manager.unsubscribe(unsub, r, e)
+
         self.manager.subscribe(unsub, resources.PORT,
                                events.BEFORE_CREATE)
         self.manager.notify(resources.PORT, events.BEFORE_CREATE, mock.ANY)

neutron_lib/tests/unit/plugins/ml2/test_api.py

@@ -17,7 +17,8 @@ from neutron_lib.tests import _base as base
 
 
 class _MechanismDriver(api.MechanismDriver):
-    bind_port = lambda s, c: c
+    def bind_port(s, c):
+        return c
 
     def initialize(self):
         pass