MB-10805: Check boundary condition

For stdout or csv, there won't be any history for backup. We
should check those boundary cases.

Change-Id: Idf73e701c9b805fa67df9a593ca17c971995856a
Reviewed-on: http://review.couchbase.org/35518
Reviewed-by: Bin Cui <bin.cui@gmail.com>
Tested-by: Bin Cui <bin.cui@gmail.com>