Use travis_terminate to fast fail

Workaround for travis-ci/travis-ci#1066

Author: dwijnand

.travis.yml

@@ -30,10 +30,10 @@ matrix:
            ALT=i686-unknown-linux-gnu
       rust: 1.31.0
       script:
-        - rustup toolchain install nightly
-        - cargo +nightly generate-lockfile -Z minimal-versions
-        - cargo -V
-        - cargo test --features=deny-warnings
+        - rustup toolchain install nightly || travis_terminate 1
+        - cargo +nightly generate-lockfile -Z minimal-versions || travis_terminate 1
+        - cargo -V || travis_terminate 1
+        - cargo test --features=deny-warnings || travis_terminate 1
       if: branch != master OR type = pull_request
 
     - env: TARGET=x86_64-unknown-linux-gnu
@@ -42,9 +42,9 @@ matrix:
       install:
         - travis_retry curl -Lf https://github.com/rust-lang-nursery/mdBook/releases/download/v0.1.7/mdbook-v0.1.7-x86_64-unknown-linux-gnu.tar.gz | tar -xz --directory=$HOME/.cargo/bin
       script:
-        - cargo test --features=deny-warnings
-        - cargo doc --no-deps
-        - (cd src/doc && mdbook build --dest-dir ../../target/doc)
+        - cargo test --features=deny-warnings || travis_terminate 1
+        - cargo doc --no-deps || travis_terminate 1
+        - (cd src/doc && mdbook build --dest-dir ../../target/doc) || travis_terminate 1
       if: branch != master OR type = pull_request
 
   exclude: