Fix SOS report extraction failure due to tar --one-top-level bug

[m4d3bug]

Problem

SOS report extraction fails with Invalid cross-device link errors on all files when using --one-top-level combined with --strip-components in GNU tar 1.34 (shipped with RHEL 9). This affects both gather_sos (control plane nodes) and gather_edpm_sos (EDPM nodes).

All SOS report directories end up empty (0 bytes), and since the original tar.xz is unconditionally deleted after the failed extraction, the data is permanently lost.

Root Cause

GNU tar 1.34 has a bug where --one-top-level combined with --strip-components triggers Invalid cross-device link errors, even when source and destination are on the same filesystem. This is not a hard link or cross-filesystem issue — it affects all file types (regular files, directories, symlinks).

Verified by testing:

# FAILS - 17273 errors, 0 files extracted
tar --one-top-level=/tmp/test --strip-components=1 -Jxf sosreport.tar.xz

# WORKS - 0 errors, 15052 files extracted
tar -C /tmp/test --strip-components=1 -Jxf sosreport.tar.xz

Fix

1. Replace --one-top-level=DIR with -C DIR in both gather_sos and gather_edpm_sos — achieves the same result (extract into a specific directory) without the bug
2. Check tar exit code before deleting the original archive — if extraction fails, the compressed file is preserved as a fallback

Testing

Tested on RHEL 9 with GNU tar 1.34:

• Before fix: all 4 sosreport directories (3 control plane + 1 EDPM) were empty with 17,000+ Invalid cross-device link errors
• After fix: 15,052 files extracted successfully (194MB)

Environment

• OpenShift 4.18.30
• openstack-must-gather image: registry.redhat.io/rhoso-operators/openstack-must-gather-rhel9:1.0
• GNU tar 1.34 (RHEL 9)

Closes #131

[openshift-ci]

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