Fix bug in TabbedPanel.remove_widget method.
Fix bug in TabbedPanel.remove_widget method.

rnixx/kivy,kivy/kivy,matham/kivy,inclement/kivy,matham/kivy,akshayaurora/kivy,kivy/kivy,inclement/kivy,akshayaurora/kivy,rnixx/kivy,matham/kivy,inclement/kivy,akshayaurora/kivy,kivy/kivy,rnixx/kivy,matham/kivy