package/rsyslog: ignore CVE-2015-3243

package/rsyslog: ignore CVE-2015-3243

https://security-tracker.debian.org/tracker/CVE-2015-3243
 "Rsyslog uses weak permissions for generating log files."

Ignoring this CVE for Buildroot as normally there are not local
users and a build could customize the rsyslog.conf to be more
restrictive ($FileCreateMode 0640).

Example fix from Alpino Linux
 https://github.com/libTorrentUser/alpino-linux-aports/commit/3cb5210cdac46fb8805d4028df16f5889f393a09

Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>