core: Replace log4j with JUL backend in dal tests

Replaces log4j with java.util.logging backend in dal tests.

Change-Id: I8994411aaada821a0d4e1127c24cbcc6baf39696
Bug-Url: https://bugzilla.redhat.com/1109871
Signed-off-by: Martin Perina <mperina@redhat.com>