kerberos: move user binaries to default output

The intention of the previous change was to move krb5-config to .dev (it
gives the locations of headers), but it grabbed all of the user-facing
binaries too. This puts them back.

nixos/tests/kerberos/mit.nix

@@ -21,7 +21,6 @@ import ../make-test.nix ({pkgs, ...}: {
       };
     };
     users.extraUsers.alice = { isNormalUser = true; };
-    environment.systemPackages = [ pkgs.krb5Full.dev ];
   };
 
   testScript = ''

pkgs/development/libraries/kerberos/krb5.nix

@@ -65,7 +65,7 @@ stdenv.mkDerivation rec {
 
   # not via outputBin, due to reference from libkrb5.so
   postInstall = ''
-    moveToOutput bin "$dev"
+    moveToOutput bin/krb5-config "$dev"
   '';
 
   enableParallelBuilding = true;