[ksk-change] Write up of key rollover experience

http://www.potaroo.net/ispcol/2010-02/rollover.html This is a writeup of the consequences of key rollover at the time when the in-addr zone operate with an unsigned root and without 5011 support. (Obviously a signed root has largely addressed this situation.) At the time there was a degree of reliance of various forms of out of band key distribution, which may have some relevance to the root key roll. Anyway, in response to a request for write ups of previous key roll experience, this is one. Geoff