Remove unnecessary xhr2 dependency
Remove unnecessary xhr2 dependency

This is a follow-up to 63a2734d3af4d1ffaf82d7acc9a9386cbc023114.

jonathanKingston/srihash.org,jonathanKingston/srihash.org,mozilla/srihash.org,mozilla/srihash.org,jonathanKingston/srihash.org