control CD eject

[flihp]

Using CDs to hold auth values means the operator has to deal with inserting and removing the CD. I've been pretty aggressive ejecting the CD drive in an attempt to keep the operator from having to manually do so. This doesn't always work out well however when we're stringing commands together in a ceremony script. The current ceremony that does a change-auth operation followed by a sign operation. In this case the change-auth command will burn the new auth value to CD and eject the drive, the sign command then needs to use the auth value which requires we close the drive in between. Having a way to opt out of these ejects would make things easier / less awkward.