Fix travis links

Author: alexcrichton

README.md

@@ -4,7 +4,7 @@ libc
 A Rust library with native bindings to the types and functions commonly found on
 various systems, including libc.
 
-[![Build Status](https://travis-ci.org/rust-lang/libc.svg?branch=master)](https://travis-ci.org/rust-lang/libc)
+[![Build Status](https://travis-ci.org/rust-lang-nursery/libc.svg?branch=master)](https://travis-ci.org/rust-lang-nursery/libc)
 [![Build status](https://ci.appveyor.com/api/projects/status/v0414slj8y8nga0p?svg=true)](https://ci.appveyor.com/project/alexcrichton/libc)
 
 [Documentation](#platforms-and-documentation)