Auto merge of #112 - servo:rustup, r=larsbergstrom
Auto merge of #112 - servo:rustup, r=larsbergstrom

Bump serde



<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/string-cache/112)
<!-- Reviewable:end -->

servo/string-cache,dzbarsky/string-cache