pkg/chrootarchive: TestChrootTarUntar fix copy/paste mistake
Introduced in 3ac6394b8082d4700483d52fbfe54914be537d9e, which makes no mention
of a reason for extracting to the same directory as we created the archive from,
so I assume this was a copy/paste mistake and the path was meant to be "dest",
not "src".
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>