tools/hv: Fix permissions of created directory and files

It's silly to create directories without execute permission, or to
give permissions to 'other' but not the group-owner.

Write the permissions in octal and 'ls -l' format since these are much
easier to read than the named macros.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Tomas Hozza <thozza@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>