core: Removed searchbackend tests stdout printing

Stopped printing (using System.out.println) in searchbackend tests since
the information printed out is useless (and even if it wasn't, logging
should have been used instead).

Change-Id: I749c91fcc6c5f3558b9af6a426a251fc20eb279d
Signed-off-by: Allon Mureinik <amureini@redhat.com>