use readlink instead of realpath so it works on rhel-6
legacy/pci_id has the same problem that legacy/whitelist had prior to !738 (merged).
J:9020200 tested this change, with passing results in RHEL6, RHEL7, RHEL8, and RHEL9.
All four recipes mentioned failures in their logs, as follows.
ERROR: /tmp/rpm-bJxJ5/kernel-2.6.32-.x86_64.rpm not a valid RPM file. This indicates a test failure.
argument is not an RPM package
cpio: premature end of archive
ERROR: /tmp/rpm-axshg/kernel-3.10.0-.x86_64.rpm not a valid RPM file. This indicates a test failure.
argument is not an RPM package
cpio: premature end of archive
ERROR: /tmp/rpm-138KT/kernel-4.18.0-.x86_64.rpm not a valid RPM file. This indicates a test failure.
ERROR: /tmp/rpm-138KT/kernel-modules-4.18.0-.x86_64.rpm not a valid RPM file. This indicates a test failure.
argument is not an RPM package
cpio: premature end of archive
argument is not an RPM package
cpio: premature end of archive
ERROR: /tmp/rpm-kE2wy/kernel-5.14.0-.x86_64.rpm not a valid RPM file. This indicates a test failure.
ERROR: /tmp/rpm-kE2wy/kernel-modules-5.14.0-.x86_64.rpm not a valid RPM file. This indicates a test failure.
argument is not an RPM package
cpio: premature end of archive
argument is not an RPM package
cpio: premature end of archive
None of those test failure
messages resulted in task failures, and similar messages have occurred in other invocations of this task, with passing results.