ToolBarManager: Let XSubToolbarController update itself
ToolBarManager: Let XSubToolbarController update itself

The doc for XSubToolbarController::updateImage says:

"gets called to notify a controller that it should set an image
which represents the current selected function.

Only the controller instance is able to set the correct image
for the current function. A toolbar implementation will ask
sub-toolbar controllers to update their image whenever it has
to update the images of all its buttons." However, it didn't
work that way until now.

Steps to reproduce:

1. Open one of the custom shapes dropdowns, and choose a shape
   other than the default. Note that the button is now updated
   with the last selection.

2. Change the icon theme. Note that the button shows now the
   default shape, despite the fact that a future activation
   of that button, will still draw the last used shape.

Change-Id: I9345c9faa17dc82a5f590b242b60751ce5d8e648
Reviewed-on: https://gerrit.libreoffice.org/16781
Tested-by: Jenkins <5a4fe08359c7f97380e408c717ef42c86939cd86@libreoffice.org>
Reviewed-by: Maxim Monastirsky <77b8aedb521df15f26b15a1fc7b56454a583664f@gmail.com>

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core