tablespace permissions failures when copying an index that is in the
database's default tablespace.  A side-effect of the change is that explicitly
specifying the default tablespace no longer triggers a permissions check;
this is not how it was done in pre-8.3 releases but is argued to be more
consistent.  Per bug #3921 from Andrew Gilligan.  (Note: I argued in the
subsequent discussion that maybe LIKE shouldn't copy index tablespaces
at all, but since no one indicated agreement with that idea, I've refrained
from doing it.)