Revert "feat(client): check server version"

This reverts commit 4d2679338755ddc4736700b33f662d41d9ba559d.
feat(controller): check client version

If the client sends a X-Deis-Version header to the server, a django
middleware class will validate and ensure that the versions are the
same. If they are not, the request is rejected, and a HttpResponse
object is returned with the client and server versions displayed.