fix test build script

`cargo test` failed because of the too long lines but the build passed
anyway because `cargo test -- --ignored` did. The script should be a
single command.

https://docs.travis-ci.com/user/deployment/script/

.travis.yml

@@ -47,9 +47,7 @@ matrix:
 script:
   - |
     if [ -z ${INTEGRATION} ]; then
-      cargo build
-      cargo test
-      cargo test -- --ignored
+      cargo build && cargo test && cargo test -- --ignored
     else
       ./ci/integration.sh
     fi