Remove grenade-nova-net template
Remove grenade-nova-net template

After the mitaka-eol cleanup this contains now a single job which
is already part of integrated gate as voting job and in some projects.
We can remove the experimental job and the template completely.

Change-Id: I5f58f4b7c0c05ffd0db95cf0f1f9dc7cc2592f92

openstack-infra/project-config,openstack-infra/project-config