Review 23902

C. Thomas Tyler
Eliminated unnecessary removal of live rdb.lbr file.

The rdb.lbr from was being removed duing the scripts that reset
a replica using offline databases.  The rdb.lbr file is not
regenerated from a checkpoint, and is not affected in the process
of regneration from a checkpoint, and thus should not be removed
in checkpoint-related processing.

Removing it was functionally mostly harmless, as the rdb.lbr
file gets regenerated and update as needed by user activity,
and also by  However, removing it unnecesarily
caused unnecessary delay in getting archive files sync'd.

The processing in switch_db_files() in
(for the UNIX/Linux implementation) expects the rdb.lbr file
to exist prior to the db swap.

#review @giles
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