Backport from trunk: Fix drag&drop crash in the folder tree.
Backport from trunk:
Fix drag&drop crash in the folder tree.

svn path=/branches/KDE/3.4/kdepim/; revision=414670

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