added sshfsFuse and screen to rescue-cd.nix

sshsfsFuse so that you can get packages from another machine easily
screen so that you can copy paste easily

svn path=/nixos/trunk/; revision=14128

installer/cd-dvd/rescue-cd.nix

@@ -190,6 +190,9 @@ rec {
         pkgs.gdb # for debugging Nix
         pkgs.testdisk # useful for repairing boot problems
         pkgs.mssys # for writing Microsoft boot sectors / MBRs
+
+        pkgs.sshfsFuse
+        pkgs.screen
       ];
     };