Fix crash during Kolab task folder refresh: - Don't emit dataChanged() during the reload, we might still have   nodes that contain dangling pointers. - Keep a copy of the todo uid in the node since we need that in the node   dtor and the todo pointer can be invalid at this point.
Fix crash during Kolab task folder refresh:
- Don't emit dataChanged() during the reload, we might still have
  nodes that contain dangling pointers.
- Keep a copy of the todo uid in the node since we need that in the node
  dtor and the todo pointer can be invalid at this point.

Kolab issue 2697

svn path=/trunk/KDE/kdepim/; revision=810804

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