Don't delete the mainwidget of a part before the part itself is deleted.
Don't delete the mainwidget of a part before the part itself is deleted.

As the parts need to do cleanup before their mainwidget is deleted, (like
calling the save method of the mainwidget).

This is equivalent to ensuring parts are deleted before the widgetstack
containing the mainwidgets of the parts is deleted.

svn path=/trunk/kdepim/kaplan/src/; revision=195231

lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi