ctdb-vacuum: change full db traverse vacuuming to fill delete queue

ctdb-vacuum: change full db traverse vacuuming to fill delete queue

This lets the "fast vacuum" delete queue traverse do the actual work.

On the positive side, we note that this lets the "full vacuuming"
treat the records that have never been migrated with data correctly.
These had previously been added to the delete list for complicated
cross-node deletion instead of directly deleting them.

On the other hand side, there might be a slight overhead
since the records are read again in the delete queu traverse,
but this is OK because this change is in preparation of
untangling the db traverse altogether from the vacuum run,
making it independent.

Signed-off-by: Michael Adam <obnox@samba.org>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>