bunzip2 takes too long

[Daniel Silverstone]

Almost 25 seconds of a 45 second build is bunzip2ing the chroot tarball.

The DebianManager buildd slave method should cache uncompressed tarballs (in fact, unpack-chroot could do it transparently)

Since we never read chroots back from the filecache, we could simply replace it in-situ and the unpack-chroot code could look to see if it's compressed and if it is, uncompress it before continuing.

It'll chew more disk, but has the potential to speed up builds a lot.

[Daniel Silverstone (dsilvers)]

This is fixed in the unpack-chroot method in v11