mount.cifs: Fix double-free issue when mounting with setuid root

mount.cifs: Fix double-free issue when mounting with setuid root

It can be easily reproduced with the following:

  # chmod +s `which mount.cifs`
  # echo "//localhost/share /mnt cifs \
    users,username=foo,password=XXXX" >> /etc/fstab
  # su - foo
  $ mount /mnt
  free(): double free detected in tcache 2
  Child process terminated abnormally.

The problem was that check_fstab() already freed orgoptions pointer
and then we freed it again in main() function.

Fixes: bf7f48f4c7dc ("mount.cifs.c: fix memory leaks in main func")
Signed-off-by: Paulo Alcantara (SUSE) <paulo@paulo.ac>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>