Rollback changed defaults and use lowercase boolean value

Problem/Motivation

The commit http://drupalcode.org/project/captcha.git/commit/c43bcc5 has changed the defaults incorrectly and does not follow core code style.

Proposed resolution

Rollback half patch

Remaining tasks

None

User interface changes

None

API changes

None

Original report:

Drupal\Core\Config\Schema\SchemaIncompleteException: Schema errors for captcha.settings with the following errors: 
captcha.settings:administration_mode variable type is integer but applied schema class is Drupal\Core\TypedData\Plugin\DataType\BooleanData, 
captcha.settings:allow_on_admin_pages variable type is integer but applied schema class is Drupal\Core\TypedData\Plugin\DataType\BooleanData, 
captcha.settings:add_captcha_description variable type is integer but applied schema class is Drupal\Core\TypedData\Plugin\DataType\BooleanData, 
captcha.settings:enable_stats variable type is integer but applied schema class is Drupal\Core\TypedData\Plugin\DataType\BooleanData, 
captcha.settings:log_wrong_responses variable type is integer but applied schema class is Drupal\Core\TypedData\Plugin\DataType\BooleanData 
in Drupal\Core\Config\Testing\ConfigSchemaChecker->onConfigSave() (line 98 of /var/lib/drupaltestbot/sites/default/files/checkout/core/lib/Drupal/Core/Config/Testing/ConfigSchemaChecker.php). Drupal\Core\Config\Testing\ConfigSchemaChecker->onConfigSave(Object, 'config.save', Object) Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('config.save', Object) Drupal\Core\Config\Config->save(1) Drupal\Core\Config\ConfigInstaller->createConfiguration('', Array) Drupal\Core\Config\ConfigInstaller->installDefaultConfig('module', 'captcha') Drupal\Core\Extension\ModuleInstaller->install(Array, 1) Drupal\simpletest\WebTestBase->setUp() Drupal\recaptcha\Tests\ReCaptchaBasicTest->setUp() Drupal\simpletest\TestBase->run(Array) simpletest_script_run_one_test('1', 'Drupal\recaptcha\Tests\ReCaptchaBasicTest')