Fixing unrecord

Dependencies

• [2] CCLLB7OI Upgrading to Sanakirja 0.15 + version bump
• [3] I52XSRUH Massive cleanup, and simplification
• [4] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).
• [5] 6YMDOZIB Refactoring apply

Change contents

• edit in libpijul/src/unrecord/mod.rs at line 514
  [2.27338]→[3.3960:4024](∅→∅),[3.3960]→[3.3960:4024](∅→∅)
  − let intro_ext = e.introduced_by.unwrap_or(change_hash);
• replacement in libpijul/src/unrecord/mod.rs at line 536
  [3.248439]→[3.248439:248499](∅→∅)
  − |h| changes.knows(&intro_ext, &h).unwrap(),
  [3.248439]

  [3.4073]
  + |h| changes.knows(&change_hash, &h).unwrap(),