Fix lettuce signup feature to match Drupal site.

lms/djangoapps/courseware/features/signup.feature

@@ -5,12 +5,12 @@ Feature: Sign in
 
   Scenario: Sign up from the homepage
     Given I visit the homepage
-    When I click the link with the text "Sign Up"
+    When I click the link with the text "Register Now"
     And I fill in "email" on the registration form with "robot2@edx.org"
     And I fill in "password" on the registration form with "test"
     And I fill in "username" on the registration form with "robot2"
     And I fill in "name" on the registration form with "Robot Two"
     And I check the checkbox named "terms_of_service"
     And I check the checkbox named "honor_code"
-    And I press the "Create My Account" button on the registration form
+    And I submit the registration form
     Then I should see "THANKS FOR REGISTERING!" in the dashboard banner

lms/djangoapps/courseware/features/signup.py

@@ -3,17 +3,18 @@
 
 from lettuce import world, step
 
+
 @step('I fill in "([^"]*)" on the registration form with "([^"]*)"$')
 def when_i_fill_in_field_on_the_registration_form_with_value(step, field, value):
-    register_form = world.browser.find_by_css('form#register_form')
+    register_form = world.browser.find_by_css('form#register-form')
     form_field = register_form.find_by_name(field)
     form_field.fill(value)
 
 
-@step('I press the "([^"]*)" button on the registration form$')
-def i_press_the_button_on_the_registration_form(step, button):
-    register_form = world.browser.find_by_css('form#register_form')
-    register_form.find_by_value(button).click()
+@step('I submit the registration form$')
+def i_press_the_button_on_the_registration_form(step):
+    register_form = world.browser.find_by_css('form#register-form')
+    register_form.find_by_name('submit').click()
 
 
 @step('I check the checkbox named "([^"]*)"$')