This caused exceptions like:
Caught exception in Hydra::Controller::Build->view_build "writing to file: Broken pipe at /nix/store/ihdb3widsq1dk7sbl5vqjxfcxb5ypad4-hydra-0.1pre1297-8158093/libexec/hydra/lib/Hydra/Controller/Build.pm line 59."
because the connection to the Nix daemon would be terminated due to a protocol violation (calling queryPathInfo with an empty string).
5OXBTB3LCJ7N4EKOLAPCRFNFH4IGFEAXWIP4WRM6G5OSCUIEDH2QC