Remove obsolete steampipe manifests
populate-depot.py now generates the equivalent of these, and puts them in SteamLinuxRuntime_whatever.tar.xz.
steamrt/tasks#388
/cc @denittis
populate-depot.py now generates the equivalent of these, and puts them in SteamLinuxRuntime_whatever.tar.xz.
steamrt/tasks#388
/cc @denittis