Prevent dragging of internal URLs.
Prevent dragging of internal URLs.

Kolab issue 2401

svn path=/branches/kdepim/enterprise/kdepim/; revision=762653

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