Fix Travis CI file to use current package name for Docker
Fix Travis CI file to use current package name for Docker

Without this change, Travis CI fails to perform the build. See:
https://github.com/travis-ci/docs-travis-ci-com/pull/1248

DavidCain/mitoc-ansible,DavidCain/mitoc-ansible,jcalazan/ansible-django-stack,DavidCain/mitoc-ansible,YPCrumble/ansible-django-stack,jcalazan/ansible-django-stack,jcalazan/ansible-django-stack,YPCrumble/ansible-django-stack,YPCrumble/ansible-django-stack