Jail update nit.
Set Content-Type appropriately.

Also ensures that plug=none requests get the latest version without causing a
write.
ScoutCamp upgrade.
New version to fix dependencies.
Chroot: save output files back in the file tree.
Sandbox shell: Erase all data in /tmp/ to avoid leaking.

That way, we avoid having both leaking information from a particular sandbox
shell run, and giving the possibility to flood the hard drive fast.