package/libcgroup: fix CVE-2018-14348

libcgroup up to and including 0.41 creates /var/log/cgred with mode 0666
regardless of the configured umask, leading to disclosure of information

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>