Blot out Travis addons on le_auto job.
Blot out Travis addons on le_auto job.

MariaDB addon is broken on Google Compute Engine jobs at the moment: see https://github.com/travis-ci/travis-ci/issues/5759.

wteiken/letsencrypt,brentdax/letsencrypt,bsmr-misc-forks/letsencrypt,stweil/letsencrypt,jsha/letsencrypt,lmcro/letsencrypt,letsencrypt/letsencrypt,stweil/letsencrypt,dietsche/letsencrypt,jtl999/certbot,DavidGarciaCat/letsencrypt,brentdax/letsencrypt,DavidGarciaCat/letsencrypt,letsencrypt/letsencrypt,jsha/letsencrypt,dietsche/letsencrypt,mitnk/letsencrypt,wteiken/letsencrypt,mitnk/letsencrypt,lmcro/letsencrypt,bsmr-misc-forks/letsencrypt,jtl999/certbot