[ksk-rollover] Updated version of "What To Expect During the Root KSK Rollover"

https://www.icann.org/en/system/files/files/ksk-rollover-expect-17sep18-en.p... There is two updates, removing the bit about the Board decision (since it is done) and adding the expected time of 1600 UTC (because the operational partners have agreed on this). We know that many people, even those who have been in the technical community a long time, have a misunderstanding of some of the topics, so we want to get this document out to as wide of a population as we can before October 11. If you have any corrections to the document, by all means let me know. --Paul Hoffman