Merge pull request #34 from y-yagi/fix_ruby_warning

Fix "warning: assigned but unused variable - visit_action"

lib/turbolinks/assertions.rb

@@ -14,7 +14,7 @@ def assert_turbolinks_visited(options = {}, message = nil)
       assert_response(:ok, message)
       assert_equal("text/javascript", response.content_type)
 
-      visit_location, visit_action = turbolinks_visit_location_and_action
+      visit_location, _ = turbolinks_visit_location_and_action
 
       redirect_is       = normalize_argument_to_redirection(visit_location)
       redirect_expected = normalize_argument_to_redirection(options)