Use the rustup.sh script from rust-lang.org.

.travis.yml

@@ -1,11 +1,5 @@
 install:
-  - curl -O http://static.rust-lang.org/dist/rust-nightly-x86_64-unknown-linux-gnu.tar.gz
-  - tar xf rust-nightly-x86_64-unknown-linux-gnu.tar.gz
-  - sudo ./rust-nightly-x86_64-unknown-linux-gnu/install.sh
-
-  - curl -O http://static.rust-lang.org/cargo-dist/cargo-nightly-linux.tar.gz
-  - tar xf cargo-nightly-linux.tar.gz
-  - sudo ./cargo-nightly/install.sh
+  - curl -s http://www.rust-lang.org/rustup.sh | sudo sh
 
 script:
   - cargo build