Update settings.KerberosErrorType enum

Sync settings.KerberosErrorType enum with the ErrorType enum in
third_party/cros_system_api/dbus/kerberos/kerberos_service.proto. This
missing type will be mapped to a general kerberos error message in
kerberos_add_account_dialog.js.

Bug: 983041
Change-Id: I9231f3b1bc5b77fd2da8e02f8ee7e25db1e4703b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2575032Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Felipe Andrade <fsandrade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835240}

chrome/browser/resources/settings/chromeos/os_people_page/kerberos_accounts_browser_proxy.js

@@ -66,6 +66,7 @@ cr.define('settings', function() {
     kParsePrincipalFailed: 18,
     kBadConfig: 19,
     kJailFailure: 20,
+    kKerberosDisabled: 21,
   };
 
   /**