classes/package_tar: fix conflicts with package_deb / package_ipk
Avoid tar noticing that the directory is changing when
do_package_write_deb or do_package_write_ipk are running at the same
time as do_package_write_tar (because DEBIAN and CONTROL are being added
and removed while tar is running so the directory changes).
Fixes [YOCTO #5652]
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
