slice is busy.  This might mean that the user will not be able to
delete the slice for a long time, but we are having problems with
users canceling slices before they finish setting up, and the XEN
client side is not handling this very well. Note that the cleanupslice
script calls GeniCM::CleanupDeadSlice() directly, which *does* kill
the monitor, so admin cleanup is not affected.

Regarding the xen client side, signals can be blocked for a really
long time while a container is setting up, and so trying to kill it
fails, and bad things ripple out. Fixing that is going to take some
time to get right, so just avoid the problem for now.