coreos/manifest

Security Fixes:

• Fall back to pam_deny in authentication (Security Brief)
• Remove login shell for operator user
• Stop disabling SHA512 password hashes in PAM
  • This restores the previous pre-PAM behavior of allowing SHA512 password hashes

Changes:

• The image signing key has been updated again, revoking the sub-key that signed 1045.0.0 and 1047.0.0 and adding a new sub-key for this and future releases.
• Add rkt-admin group which has access to /etc/rkt
• GCE images are now provisioned by Ignition instead of coreos-cloudinit

Updates:

• Linux 4.6
• rkt 1.6.0
• Ignition 0.6.0
• coreos-cloudinit 1.11.0
• Google Compute Daemon 1.3.2