Test also removing unwanted boolean attrs

Author: dedene

test/html5/test_sanitizer.rb

@@ -201,7 +201,7 @@ def test_should_allow_contenteditable
   end
 
   def test_boolean_attributes
-    input = "<video controls></video>"
+    input = "<video controls download></video>"
     expected_html5 = "<video controls=''></video>"
     output_html5 = sanitize_html5(input).tr('"', "'")