Handle the special case that the ioslave could not be started and show 'Unknown error n' if KIO::buildErrorString() returns an empty string.
Handle the special case that the ioslave could not be started and show 'Unknown error n' if KIO::buildErrorString() returns an empty string.

svn path=/trunk/KDE/kdepim/; revision=656526

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