Update rustfmt version used by Travis

Author: djwf

.travis.yml

@@ -7,7 +7,7 @@ rust:
 
 install:
   # Install rustfmt
-  - curl -LSfs https://japaric.github.io/trust/install.sh | sh -s -- --force --crate rustfmt --git japaric/rustfmt-bin --tag v0.6.3-20161120
+  - curl -LSfs https://japaric.github.io/trust/install.sh | sh -s -- --force --crate rustfmt --git japaric/rustfmt-bin --tag v0.7.1-20170120
   # Install clippy
   - if [ "$TRAVIS_RUST_VERSION" = "nightly" ]; then (cargo install clippy --force) fi
   - export PATH=$HOME/.cargo/bin:$PATH