Work around the model not wanting to display the content of a search folder as it doesn't have any content mimetypes set.
Work around the model not wanting to display the content of a search
folder as it doesn't have any content mimetypes set.

svn path=/trunk/kdesupport/akonadi/; revision=996438

kolab-groupware/akonadi,kolab-groupware/akonadi,kolab-groupware/akonadi,kolab-groupware/akonadi