s/rustfmt-preview/rustfmt/

Author: phansch

Diff for: .travis.yml

@@ -30,7 +30,7 @@ before_install:
 install:
   - |
     if [ -z ${INTEGRATION} ]; then
-      rustup component add rustfmt-preview || cargo install --git https://github.com/rust-lang/rustfmt/ --force
+      rustup component add rustfmt || cargo install --git https://github.com/rust-lang/rustfmt/ --force
       if [ "$TRAVIS_OS_NAME" == "linux" ]; then
         . $HOME/.nvm/nvm.sh
         nvm install stable