When a newsgroup does not exist anymore, display a better error message than "the file or directory blabla does not exist"...
When a newsgroup does not exist anymore, display a better error message than "the file or directory blabla does not exist"...

svn path=/trunk/KDE/kdepim/knode/; revision=1014744

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