unpack_dvd does not parse .treeinfo as an INI file

Description

To safely support EL8+ ISOs, unpack_dvd should parse .treeinfo as an ini file and read discattr data from the appropriate sections.

As noted in SIMP-8621, there are two possible data structures in ISO .treeinfo files; the legacy "pre-productmd" format (with all informatino under [general], and the "pre-productmd" format, which provides release information under [release] and provides variant repo under [variant-*] setctions.

However, the unpack_dvd script currently does not read .treeinfo as an ini at all, but naively greps lines without considering the section it is in or if there are matches in multiple sections.

Acceptance Criteria

None

Epic Link

Story Points

None

Components

Affects versions

Priority

Medium
Configure