[faiproject/fai] 572319: fix perl warning

[Mrfai]

  Branch: refs/heads/master
  Home:   https://github.com/faiproject/fai
  Commit: 5723195fe19fd2e6585e9dd582f2977e3e18a46d
      https://github.com/faiproject/fai/commit/5723195fe19fd2e6585e9dd582f2977e3e18a46d
  Author: Thomas Lange <lange at debian.org>
  Date:   2022-05-28 (Sat, 28 May 2022)

  Changed paths:
    M lib/setup-storage/Commands.pm

  Log Message:
  -----------
  fix perl warning