overrides: Fix Gtk.Adjustment.__init__ overrides not setting "value" sometimes. Fixes #151
Gtk.Adjustment allows passing positional arguments to init which get translated to a dict for passing to GObject.Object.init. In case of the first argument "value", if "value" is passed before the upper and lower bound to Object.init it will be set to 0 instead.
In Python 2 this happened to work (at least on my machine) because "value" got placed after the bounds (in terms of iteration order) in the final dict value passed to Object.init.
To work around this, set "value" again after init(). A similar work around already exists when "value" is passed as a kwarg.