hydra-eval-jobset: $firstOutput is not used so can be removed

Dependencies

• [2] VU2OLHD2 Move most of AddBuilds to hydra-eval-jobset
• [3] 6HWIUOSU Avoid fetching Projects/Jobsets just to get the name column
• [4] HP5WJLQU hydra-eval-{jobs,jobset}: Pass file name as <...>
• [*] N22GPKYT * Put info about logs / build products in the DB.

Change contents

• edit in src/script/hydra-eval-jobset at line 434
  [2.14221]→[2.14221:14350](∅→∅)
  − # Only check one output: if it's the same, the other will be as well.

  − my $firstOutput = $outputNames[0];