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/plugins/common.py

@@ -299,9 +299,8 @@ class Addr(object):
             # too long, truncate
             addr_list = addr_list[0:len(result)]
         append_to_end = False
-        for i in range(0, len(addr_list)):
-            block = addr_list[i]
-            if len(block) == 0:
+        for i, block in enumerate(addr_list):
+            if not block:
                 # encountered ::, so rest of the blocks should be
                 # appended to the end
                 append_to_end = True