Fix crash when collapsing items with constraints (dependencies).
Fix crash when collapsing items with constraints (dependencies).

svn path=/trunk/KDE/kdepim/; revision=789559

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