Remove LACOUNT and LACCESSOR and migrate the records immediately.

Remove LACOUNT and LACCESSOR and migrate the records immediately.

This concept didnt work out and it is really just as expensive as a full migration
anyway, without the benefit of caching the data for subsequence accesses.

Now, migrate the records immediately on first access.
This will be combined with a "cheap vacuum-lite" for special empty records to
prevent growth of databases.

Later extensions to mimic read-only behaviour of records will include proper shared read-only locking of database records, making the laccessor/lacount read-only access to the data obsolete anyway.

By removing this special case and handling of lacount laccessor makes the codapath where shared read-only locking will be be implemented simpler, and frees up space in the ctdb_ltdb header for use by vacuuming flags as well as read-only locking flags.

(This used to be ctdb commit 155dd1f4885fe142c6f8bd09430f65daf8a17e51)