Make sure that we have a pristine source tree after do_unpack.
[YOCTO #9064]
(From OE-Core rev: eccae514b71394ffaed8fc45dea7942152a334a1)
(From OE-Core rev: 696dd4607766a07fcdbb7e6bfc07f3b815bc9d5c)
Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>