docs(ngController): fix e2e test

The changes made in 2a156c2 caused this test
to fail. The test was trying to find an anchor with specified text but the
anchor had changed to a button.

Author: petebacondarwin

src/ng/directive/ngController.js

@@ -127,12 +127,12 @@
  *       expect(secondRepeat.element(by.model('contact.value')).getAttribute('value'))
  *           .toBe('john.smith@example.org');
  *
- *       firstRepeat.element(by.linkText('clear')).click();
+ *       firstRepeat.element(by.buttonText('clear')).click();
  *
  *       expect(firstRepeat.element(by.model('contact.value')).getAttribute('value'))
  *           .toBe('');
  *
- *       container.element(by.linkText('add')).click();
+ *       container.element(by.buttonText('add')).click();
  *
  *       expect(container.element(by.repeater('contact in settings.contacts').row(2))
  *           .element(by.model('contact.value'))
@@ -210,12 +210,12 @@
  *      expect(secondRepeat.element(by.model('contact.value')).getAttribute('value'))
  *          .toBe('john.smith@example.org');
  *
- *      firstRepeat.element(by.linkText('clear')).click();
+ *      firstRepeat.element(by.buttonText('clear')).click();
  *
  *      expect(firstRepeat.element(by.model('contact.value')).getAttribute('value'))
  *          .toBe('');
  *
- *      container.element(by.linkText('add')).click();
+ *      container.element(by.buttonText('add')).click();
  *
  *      expect(container.element(by.repeater('contact in contacts').row(2))
  *          .element(by.model('contact.value'))