lib/result_root.rb: resolve rubocop Naming/AccessorMethodName issue

[rli9]

Reproduce

lkp-tests$ rubocop lib/result_root.rb
lib/result_root.rb:101:7: C: Naming/AccessorMethodName: Do not prefix writer method names with set_.
  def set_date_glob(glob)
      ^^^^^^^^^^^^^
lib/result_root.rb:105:7: C: Naming/AccessorMethodName: Do not prefix writer method names with set_.
  def set_date(time)
      ^^^^^^^^
lib/result_root.rb:109:7: C: Naming/AccessorMethodName: Do not prefix writer method names with set_.
  def set_queue(queue)
      ^^^^^^^^^

Reference
https://github.com/intel/lkp-tests/wiki/Coding-Standard#rubocop