Security updates for Thursday

CentOS has updated thunderbird (C7; C6; C5: multiple vulnerabilities).

Fedora has updated libpng (F23:two vulnerabilities).

openSUSE has updated grub2 (42.1:code execution).

Red Hat has updated kernel(RHEL6: two vulnerabilities).

Scientific Linux has updated thunderbird (multiple vulnerabilities).

Ubuntu has updated libpng (twovulnerabilities) and pygments (code execution).