Reset local storage between qa tests

This is not done by default as it is said to incur a performance hit,
paired with local storage not always being used by the site being
tested.
(https://github.com/teamcapybara/capybara/issues/1702#issuecomment-219483444)

GitLab uses localStorage, for things like remembering which tab you used
last (on the login page for example, between sign-in, ldap, and register)

Fixes: https://gitlab.com/gitlab-org/gitlab-qa/issues/303

qa/qa/runtime/browser.rb

@@ -72,6 +72,7 @@ module QA
           Capybara::Selenium::Driver.new(
             app,
             browser: :chrome,
+            clear_local_storage: true,
             desired_capabilities: capabilities,
             options: options
           )