Fix DBError output in test logs

After patch If48ba9d3deb54f8e9ea1ed1987f832ddbaed33fc a (non-fatal) DBError
is displayed during unit tests run.
This patch fixes that by proper mocking (and stops mixing mock and mox
in single unit test).

Change-Id: I2bd857492d2fca7f3683f7b7a6b062e3dddcbeed
Merge "Fix DBError output in test logs"