Fix local privilege escalation in IRET handler. [SA-15:21]

Fix local privilege escalation in IRET handler. [SA-15:21]

Fix OpenSSH multiple vulnerabilities. [SA-15:22]

Disabled ixgbe(4) flow-director support. [EN-15:14]

Fix insufficient check of unsupported pkg(7) signature methods.
[EN-15:15]

Approved by:	so

git-svn-id: svn://svn.freebsd.org/base/releng/10.1@287146 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f