Add save_path method to support Capybara 3
Add save_path method to support Capybara 3

Capybara.save_and_open_page_path method
removed at https://github.com/teamcapybara/capybara/commit/15f5005ff802d23c4c2e76530354ed8217550f13
Use save_path method instead of save_and_open_page_path
from Capbyara 3.0.0.rc1

test-unit/test-unit-capybara