Ticket #3021: mc segfaults when mc's tempdir doesn't belong to the correct user.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Merge branch '3021_segfault_unowned_temp_dir'

* 3021_segfault_unowned_temp_dir:
  Ticket #3021: mc segfaults when mc's tempdir doesn't belong to the correct user.