The IEEE OUI, IAB, and OUI-36 lists currently redirect to

The IEEE OUI, IAB, and OUI-36 lists currently redirect to
http://standards.ieee.org/regauthmaint.html, which says

IEEE Registration Authority Services will be unavailable from Friday, December 27th through Monday, December 30th

As a result the manuf file got clobbered. Revert the manuf file to
its non-clobbered state and add sanity checks to make-manuf. Add a
note about the impending addition of OUI-28.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@54485 f5534014-38df-0310-8fa8-9805f1628bb7