[yast/yast-security] 0fc99c: Simplify the Y2Security::Selinux#config_file method

11 Feb 2021

      Branch: refs/heads/refactor-selinux-config
  Home:   https://github.com/yast/yast-security
  Commit: 0fc99c5cf22f61fe61d31db557b08f5dbcb76cfc
      https://github.com/yast/yast-security/commit/0fc99c5cf22f61fe61d31db557b08f5...
  Author: David Díaz González <dgonzalez@suse.de>
  Date:   2021-02-11 (Thu, 11 Feb 2021)

  Changed paths:
    M src/lib/y2security/selinux.rb

  Log Message:
  -----------
  Simplify the Y2Security::Selinux#config_file method

By using `||=` for memoization.