Fix Pylint upgrade issues

* Remove unsupported pylint disable options
    * star-args removed in Pylint 1.4.3
    * abstract-class-little-used removed in Pylint 1.4.3

* Fixes new lint errors

* Copy dummy-variable-rgx expression to new ignored-argument-names expression to ignore unused funtion arguments

* Notable changes
    * Refactor to satisfy Pylint no-else-return warning
    * Fix Pylint inconsistent-return-statements warning
    * Refactor to satisfy consider-iterating-dictionary
    * Remove methods with only super call to satisfy useless-super-delegation
    * Refactor too-many-nested-statements where possible
    * Suppress type checked errors where member is dynamically added (notably derived from josepy.JSONObjectWithFields)
    * Remove None default of func parameter for ExitHandler and ErrorHandler

Resolves #5973

certbot/cli.py

@@ -293,8 +293,7 @@ def config_help(name, hidden=False):
     """Extract the help message for an `.IConfig` attribute."""
     if hidden:
         return argparse.SUPPRESS
-    else:
-        return interfaces.IConfig[name].__doc__
+    return interfaces.IConfig[name].__doc__
 
 
 class HelpfulArgumentGroup(object):
@@ -510,7 +509,7 @@ class HelpfulArgumentParser(object):
     # Help that are synonyms for --help subcommands
     COMMANDS_TOPICS = ["command", "commands", "subcommand", "subcommands", "verbs"]
     def _list_subcommands(self):
-        longest = max(len(v) for v in VERB_HELP_MAP.keys())
+        longest = max(len(v) for v in VERB_HELP_MAP)
 
         text = "The full list of available SUBCOMMANDS is:\n\n"
         for verb, props in sorted(VERB_HELP):
@@ -538,7 +537,7 @@ class HelpfulArgumentParser(object):
             apache_doc = "(the certbot apache plugin is not installed)"
 
         usage = SHORT_USAGE
-        if help_arg == True:
+        if help_arg is True:
             self.notify(usage + COMMAND_OVERVIEW % (apache_doc, nginx_doc) + HELP_USAGE)
             sys.exit(0)
         elif help_arg in self.COMMANDS_TOPICS:
@@ -839,8 +838,7 @@ class HelpfulArgumentParser(object):
             return dict([(t, True) for t in self.help_topics])
         elif not chosen_topic:
             return dict([(t, False) for t in self.help_topics])
-        else:
-            return dict([(t, t == chosen_topic) for t in self.help_topics])
+        return dict([(t, t == chosen_topic) for t in self.help_topics])
 
 def _add_all_groups(helpful):
     helpful.add_group("automation", description="Flags for automating execution & other tweaks")