vzctl_env_convert_ploop(): fix mkdir mode

It should be 0700 not 0600. As a result, a container converted to ploop
had wrong mode:

 # ls -ld /vz/private/1031
 drw------- 3 root root 4096 Jul  3 03:35 /vz/private/1031

Signed-off-by: Kir Kolyshkin <kir@openvz.org>
1 file changed