Bug 14116: Silence noisy output for t/Scrubber.

Bug 14116: Silence noisy output for t/Scrubber.

Why diag or print out things, unless it is -v?
And why print anything except success or failure type messages?
This cleans up the output.

TEST PLAN
---------
1) $ prove t/Scrubber.t
   -- there's some noise.
2) apply patch
3) $ prove t/Scrubber.t
   -- noise issue resolved.
      Output is still reasonable for -v.
4) koha qa test tools

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>