MFH: r459011 r459013 r459492

net-p2p/transmission-daemon: Mitigate DNS rebinding attack

Incorporate upstream pull request 468, proposed by Tavis Ormandy from
Google Project Zero, which mitigates this attack by requiring a host
whitelist for requests that cannot be proven to be secure, but it can
be disabled if a user does not want security.

PR: 225150
Submitted by: Tavis Ormandy
Approved by: crees (maintainer)
Obtained from: https://github.com/transmission/transmission/pull/468#issuecomment-357098126
Security: https://www.vuxml.org/freebsd/3e5b8bd3-0c32-452f-a60e-beab7b762351.html

Add note to UPDATING for net-p2p/transmission-daemon explaining how to
allow client access with the new DNS rebinding mitigations.

PR: 225150
Security: https://www.vuxml.org/freebsd/3e5b8bd3-0c32-452f-a60e-beab7b762351.html

net-p2p/transmission-daemon: Improve UPDATING entry and add pkg-message

This will ensure users who do not read UPDATING are still presented with
the message about how to allow clients to connect to the daemon using
DNS when they upgrade the package.

PR: 225150
Reported by: swills
Security: https://www.vuxml.org/freebsd/3e5b8bd3-0c32-452f-a60e-beab7b762351.html

Approved by: ports-secteam (swills)