Drop unused rustc-serialize dependency.

Cargo.toml

@@ -27,7 +27,6 @@ git = "https://github.com/servo/mozjs"
 [dependencies]
 lazy_static = "0.2.1"
 libc = "0.2"
-rustc-serialize = "0.3"
 log = "0.3"
 heapsize = ">=0.2, <0.4"
 num-traits = "0.1.32"

src/lib.rs

@@ -23,7 +23,6 @@ extern crate libc;
 extern crate log;
 extern crate mozjs_sys;
 extern crate num_traits;
-extern crate rustc_serialize as serialize;
 
 pub mod jsapi {
     use libc::FILE;