Don't display still is the status bar, that there is one message in the folder

after the last has been deleted.

svn path=/trunk/kdenetwork/kmail/; revision=79381

kmheaders.cpp

@@ -885,6 +885,7 @@ void KMHeaders::deleteMsg (int msgId)
     // We are in the trash folder -> really delete messages
     moveMsgToFolder(NULL, msgId);
   }
+  mOwner->statusMsg("");
   //  triggerUpdate();
 }