Pass ui.registerthread an Account() and not a name as string

This way, we can use all the account functions such as set_abort_event()
from the ui if needed.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>

offlineimap/ui/Machine.py

@@ -42,9 +42,9 @@ class MachineUI(UIBase):
         self.logger.warning("%s:%s:%s:%s" % (
                 'warn', '', currentThread().getName(), msg))
 
-    def registerthread(s, account):
-        UIBase.registerthread(s, account)
-        s._printData('registerthread', account)
+    def registerthread(self, account):
+        super(MachineUI, self).registerthread(self, account)
+        self._printData('registerthread', account)
 
     def unregisterthread(s, thread):
         UIBase.unregisterthread(s, thread)