fix phpunit path

Author: halnique

.travis.yml

@@ -17,7 +17,7 @@ before_script:
   - chmod -R 777 build/logs
 
 script:
-  - phpunit --coverage-clover build/logs/clover.xml
+  - vendor/bin/phpunit --coverage-clover build/logs/clover.xml
 
 after_success:
   - travis_retry php vendor/bin/php-coveralls