Who has last initialized the administrative tables,
who is making all the changes, and who is expected to
either commit or re-initialize (ABORT-TRANSACTION).
tRPAdminOwner is advisory only. Before beginning a transaction,
read tRPAdminOwner. If it is empty then proceed with the configuration.
Set tRPAdminOwner after setting tRPAdminControlApply so
that other users will be advised to not make changes to the Admin
tables.
Agent sets tRPAdminOwner to empty string after tRPAdminControlApply
is set - either by user initializing or committing,
or by agent timing out the uncommitted transactions
(tRPAdminLastSetTimer).