Use vendor version of PHPUnit

Author: dantleech

.travis.yml

@@ -40,7 +40,7 @@ before_script:
   - ./tests/travis_${TRANSPORT}.sh
 
 script: 
-  - phpunit -c tests/phpunit_${TRANSPORT}.xml.dist
+  - ./vendor/bin/phpunit -c tests/phpunit_${TRANSPORT}.xml.dist
   - if [ "$PHPBENCH" = "yes" ]; then php vendor/bin/phpbench run --report=all; fi;