nexthop: initialize extack in nh_res_bucket_migrate()

These records connect through source-stated identifiers. Shared identifiers or dates alone do not establish shared exposure, root cause or applicability.

CVE-2026-64576 · Microsoft / collected KEV context

cve-program · CVE-2026-64576

• https://git.kernel.org/stable/c/eacd2e2117e8682f937967fda1022e7f1c22d91a
• https://git.kernel.org/stable/c/37bbd7e1d8df0bec3d187e961783e20c30533d2c
• https://git.kernel.org/stable/c/c0936c131a71657afc635d0db2ab096d15d473e1
• https://git.kernel.org/stable/c/3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d
• https://git.kernel.org/stable/c/d536bf205c71f700f6de2086038c3e1d77724715
• https://git.kernel.org/stable/c/18506d7263768d76ac8e057ba55a4d9da50aad66
• https://git.kernel.org/stable/c/6347c5314cee49f364aaf2e40ff15415a57a116e

No related operational record is retained in the current change model.