make_chroot: move tarball unpack to cros_sdk

Now that cros_sdk unpacks & inits the version for us, delete it here.

BUG=b:191307774
TEST=`cros_sdk` still works

Change-Id: I7539e0cc9341b8ef0badd21f47f0273c0752600b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2971574
Reviewed-by: Alex Klein <saklein@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
1 file changed