Crash on unselecting "not today" plugin

[Nimit Shah]

Steps to reproduce:

1. Go to edit -> plugins and select "not today" plugin
2. Unselect plugin

Expected: The plugin should be de activated
Actual: Attribute error with this traceback:
Traceback (most recent call last):
  File "/usr/share/gtg/GTG/gtk/plugins.py", line 263, in on_plugin_toggle
    self.pengine.deactivate_plugins([plugin])
  File "/usr/share/gtg/GTG/core/plugins/engine.py", line 233, in deactivate_plugins
    plugin.instance.deactivate(api)
  File "/usr/share/gtg/GTG/plugins/not_today/not_today.py", line 36, in deactivate
    self._gtk_deactivate()
  File "/usr/share/gtg/GTG/plugins/not_today/not_today.py", line 73, in _gtk_deactivate
    if self.toolbar_entry:
AttributeError: notToday instance has no attribute 'toolbar_entry'

[Izidor Matušov (izidor)]

Fixed in rev. 1265.