Use new-style classes consistently for Python 3 support.

Also add the fixer for this to our list of fixers we check.

bots/zephyr_mirror_backend.py

@@ -44,7 +44,7 @@ import select
 
 DEFAULT_SITE = "https://api.zulip.com"
 
-class States:
+class States(object):
     Startup, ZulipToZephyr, ZephyrToZulip, ChildSending = list(range(4))
 CURRENT_STATE = States.Startup
 

integrations/perforce/git_p4.py

@@ -824,13 +824,13 @@ def wildcard_present(path):
     m = re.search("[*#@%]", path)
     return m is not None
 
-class Command:
+class Command(object):
     def __init__(self):
         self.usage = "usage: %prog [options]"
         self.needsGit = True
         self.verbose = False
 
-class P4UserMap:
+class P4UserMap(object):
     def __init__(self):
         self.userMapFromPerforceServer = False
         self.myP4UserId = None