Merge branch 'master' into closure-size

Comparison to master evaluations on Hydra:
  - 1255515 for nixos
  - 1255502 for nixpkgs

nixos/modules/programs/fish.nix

@@ -101,6 +101,9 @@ in
       end
     '';
 
+    # include programs that bring their own completions
+    environment.pathsToLink = [ "/share/fish/vendor_completions.d" ];
+
     environment.systemPackages = [ pkgs.fish ];
 
     environment.shells = [

nixos/modules/programs/ssh.nix

@@ -189,6 +189,7 @@ in
 
         # Allow DSA keys for now. (These were deprecated in OpenSSH 7.0.)
         PubkeyAcceptedKeyTypes +ssh-dss
+        HostKeyAlgorithms +ssh-dss
 
         ${cfg.extraConfig}
       '';