Ensures that tomcat8 role works with tags.

[dbernstein]

Resolves: Islandora/documentation#979

I have tested it and verified that it works.

This can be tested by updating the Islandora-Devos/claw-playbook/requirements.yml so that the tomcat8 plugin points to this branch:

- src: https://github.com/dbernstein/ansible-role-tomcat8
   name: Islandora-Devops.tomcat8
   version: issue-979

[seth-shaw-unlv]

I applied the PR and ran ansible-playbook -i inventory/vagrant -t fcrepo-syn,tomcat8 -u vagrant playbook.yml. It ran all the indicated tasks as advertised.