Avoid `None` as a redundant argument to dict.get()

`dict.get()` returns `None` by default, if a key wasn't found.
Removing `None` as second argument to avoid redundancy.

Change-Id: I810854f50257b9dc805248ff1017521cc82d5d73

keystone/revoke/model.py

@@ -73,7 +73,7 @@ def blank_token_data(issued_at):
 class RevokeEvent(object):
     def __init__(self, **kwargs):
         for k in REVOKE_KEYS:
-            v = kwargs.get(k, None)
+            v = kwargs.get(k)
             setattr(self, k, v)
 
         if self.domain_id and self.expires_at:

keystone/tests/unit/core.py

@@ -275,7 +275,7 @@ def new_endpoint_ref(service_id, interface='public',
 
     if region_id is NEEDS_REGION_ID:
         ref['region_id'] = uuid.uuid4().hex
-    elif region_id is None and kwargs.get('region', None) is not None:
+    elif region_id is None and kwargs.get('region') is not None:
         # pre-3.2 form endpoints are not supported by this function
         raise NotImplementedError("use new_endpoint_ref_with_region")
     else:

keystone/tests/unit/fakeldap.py

@@ -535,7 +535,7 @@ class FakeLdap(core.LDAPHandler):
         self._ldap_options[option] = invalue
 
     def get_option(self, option):
-        value = self._ldap_options.get(option, None)
+        value = self._ldap_options.get(option)
         return value
 
     def search_ext(self, base, scope,