$ sudo apt-get install -t jessie-backports python-sphinx

To solve some problems with the build of the documentation, we have had to move to the version of python-sphinx available in jessie-backports. (Essentially, our documentation is now so large that it is causing problems for the theme we've chosen and we've had to make some changes to keep improve the navigation within the pages.)

If you are building lava-server in sbuild, there is an addition option required to sbuild:

--build-dep-resolver=aptitude

The build script in the lava-dev package uses this option already.