Ticket #3073: urar helper: fix handling filenames with spaces for unrar v5.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Merge branch '3073_urar5_spaces_fix'

* 3073_urar5_spaces_fix:
  Ticket #3073: urar helper: fix handling filenames with spaces for unrar v5.