
The reference to v2/index doesn't exist, causing the build to fail. Given the api-ref documentation is currently empty, removing the toctree wont cause any issues. This makes the build green (test with `tox -e api-ref`), which will allow CI to be enabled which may help further work on the api-ref. Change-Id: I9893c3f629255ae2ae879a60fa341e3775b426ed