Elasticsearch: start service automatically.

The Elasticsearch service is only started when provisioning. When provisioning
is skipped (after a halt and then up), Elasticsearch would not be running.

As described in the Elasticsearch documentation we can start the service
automatically: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/setup-service.html#_debian_ubuntu
Merge pull request #290 from madewithlove/develop

Elasticsearch: start service automatically.
Improve feature according to @fideloper feedback
Deleted magic zeros
Improve feature according to @fideloper feedback
Merge branch 'develop' of github.com:montogeek/Vaprobash into develop
Merge pull request #292 from montogeek/develop

Improve feature according to @fideloper feedback
Removed 'mariadb_version' variable that doesn't exist anymore
Merge pull request #301 from Ilyes512/fix-mariadb

Removed 'mariadb_version' variable that doesn't exist anymore
forcing yes on apache install, adding apt-key updates for php/apache
updated FPM to only listen to localhost (127.0.0.1) clients - in this case, nginx