GmailMaildir.py Removed parent class for super call

The super() call in Python 3 does not need the parent class. The MRO get it.

offlineimap/repository/GmailMaildir.py

@@ -29,8 +29,7 @@ class GmailMaildirRepository(MaildirRepository):
     def __init__(self, reposname, account):
         """Initialize a MaildirRepository object.  Takes a path name
         to the directory holding all the Maildir directories."""
-
-        super(GmailMaildirRepository, self).__init__(reposname, account)
+        super().__init__(reposname, account)
 
     def getfoldertype(self):
         return GmailMaildirFolder