baseview: Do not reset init state

Commit b5fdf34c was incomplete and still triggered updates. Make sure
BaseView does not reset the init state unwanted.

gnomemusic/views/baseview.py

@@ -194,7 +194,6 @@ class BaseView(Gtk.Stack):
 
     @log
     def _populate(self, data=None):
-        self._init = True
         self.populate()
 
     @log