utf8foldernames: fix missing decode argument

Github-ref: https://github.com/OfflineIMAP/offlineimap/issues/502
Tested-by: https://github.com/pprw
Reviewed-by: Ilias Tsitsimpis <i.tsitsimpis@gmail.com>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

offlineimap/repository/Gmail.py

@@ -19,6 +19,7 @@
 from offlineimap.repository.IMAP import IMAPRepository
 from offlineimap import folder, OfflineImapError
 
+
 class GmailRepository(IMAPRepository):
     """Gmail IMAP repository.
 
@@ -87,9 +88,9 @@ class GmailRepository(IMAPRepository):
     def getpreauthtunnel(self):
         return None
 
-    def getfolder(self, foldername):
+    def getfolder(self, foldername, decode=True):
         return self.getfoldertype()(self.imapserver, foldername,
-                                    self)
+                                    self, decode)
 
     def getfoldertype(self):
         return folder.Gmail.GmailFolder