Disable ok button when text is empty
Disable ok button when text is empty

svn path=/trunk/kdepim/; revision=226296

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