tar exists with 1 and produces warning "file changed as we read it"
if content is changed while tar archives it. Even hardlinking content
causes tar to fail this way as it changes file ctime.
Other tasks running in parallel with do_image_tar may need to hardlink
rootfs content in order to change it, e.g. do_image_wic does this to
update etc/fstab.
Ignored tar exit code 1 to be able to hardlink rootfs content while
do_rootfs_tar is tarring it.
[RP: Removed bashism]
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
