Update travis.yml to run 5.5.9 - #178
Update travis.yml to run 5.5.9 - #178

Fix #178: Add PHP 5.5.9

Signed-off-by: Rogerio Prado de Jesus <2c195cbc93efbe99210d17024a1791a17497caa8@gmail.com>

hirak/php-build,stof/php-build,gerardroche/php-build,rogeriopradoj/php-build,michael-berlin/php-build,php-build/php-build,stof/php-build,circleci/php-build,0livier/php-build,hnw/php-build