Deprecate trusty for vagrantfile
Deprecate trusty for vagrantfile

We use the vagrantfile for uploading a new docker image for the cpi
pipelines.

Co-authored-by: Denis Langer <f826c7ee1fc706b231db6dd63f95f6e5387ffd77@sap.com>

cloudfoundry-incubator/bosh-openstack-cpi-release,cloudfoundry-incubator/bosh-openstack-cpi-release,cloudfoundry-incubator/bosh-openstack-cpi-release