set correct phpunit execution

Author: peter279k

.travis.yml

@@ -10,7 +10,7 @@ before_script:
 
 script:
   - mkdir -p build/logs
-  - phpunit -c tests/phpunit.xml --coverage-clover build/logs/clover.xml tests
+  - php vendor/bin/phpunit -c tests/phpunit.xml --coverage-clover build/logs/clover.xml tests
 
 after_script:
   - php ./vendor/bin/coveralls -v