before this change, we don't error out even if pigz fails. but
there is chance that pigz fails to create the gzip'ed relocatable
tarball either due to environmental issues or some other problems,
and we are not aware of this until packaging scripts like
`reloc/build_rpm.sh` tries to ungzip this corrupted gzip file.
in this change, if pigz's status code is not 0, the status code
is printed, and create-relocatable-package.py will return 1.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#13459
dcce0c96a9