[Notification] ValueError: invalid literal for int() with base 10

[Cas]

The Notification plugin threw this error when changing settings in WebUI Preferences.

develop HEAD @ [41fed16d0888754]

15:31:58.132 [ERROR   ][deluge.ui.client                   :157 ] RPCError Message Received!
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RPCRequest: notifications.set_config({u'smtp_port': u'', u'smtp_recipients': [], u'smtp_tls': False, u'smtp_enabled': False, u'subscriptions': {u'email': []}})
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ValueError
invalid literal for int() with base 10: '': Traceback (most recent call last):
  File "/home/ubuntu/deluge.git/deluge/core/rpcserver.py", line 293, in dispatch
    ret = self.factory.methods[method](*args, **kwargs)
  File "/home/ubuntu/deluge.git/deluge/plugins/Notifications/deluge/plugins/notifications/core.py", line 208, in set_config
    self.config[key] = config[key]
  File "/home/ubuntu/deluge.git/deluge/config.py", line 148, in __setitem__
    return self.set_item(key, value)
  File "/home/ubuntu/deluge.git/deluge/config.py", line 189, in set_item
    value = oldtype(value)
ValueError: invalid literal for int() with base 10: ''

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15:31:58.133 [ERROR   ][deluge.ui.web.json_api             :1172] [Failure instance: Traceback (failure with no frames): <class 'deluge.error.WrappedException'>: invalid literal for int() with base 10: ''
Traceback (most recent call last):
  File "/home/ubuntu/deluge.git/deluge/core/rpcserver.py", line 293, in dispatch
    ret = self.factory.methods[method](*args, **kwargs)
  File "/home/ubuntu/deluge.git/deluge/plugins/Notifications/deluge/plugins/notifications/core.py", line 208, in set_config
    self.config[key] = config[key]
  File "/home/ubuntu/deluge.git/deluge/config.py", line 148, in __setitem__
    return self.set_item(key, value)
  File "/home/ubuntu/deluge.git/deluge/config.py", line 189, in set_item
    value = oldtype(value)
ValueError: invalid literal for int() with base 10: ''

]
None

[Cas]

Fixed: develop [bc50f6e5f695] and 1.3 [f870741d9de3]