Update .travis.yml to run tests but not coverage

- coverage has been failing for an unknown reason

Author: hmerritt

.travis.yml

@@ -9,7 +9,7 @@ install:
 
 script:
   - mkdir -p build/logs
-  - php vendor/bin/phpunit --coverage-clover build/logs/clover.xml
+  - composer test
 
 after_script:
   - travis_retry php vendor/bin/php-coveralls -v