retry-on-http-error=429

So that wget doesn't fail on Error 429 from Github

.travis.yml

@@ -158,7 +158,7 @@ before_script:
     # Install composer packages, will also trigger dump-autoload
     - travis_retry composer install --no-interaction --prefer-dist
     # Install coveralls.phar
-    - wget -c -nc --retry-connrefused --tries=0 https://github.com/satooshi/php-coveralls/releases/download/v1.1.0/coveralls.phar
+    - wget -c -nc --retry-connrefused --tries=0 --retry-on-http-error=429 https://github.com/satooshi/php-coveralls/releases/download/v1.1.0/coveralls.phar
     - chmod +x coveralls.phar
     - php coveralls.phar --version