tests: Fix db_test err file to expect error code name instead of value

Previous commit changed db_test to output code names to fix issues on
some platforms (I guess due to different error code values), but somehow
this log line was not updated.

Fixes: 8b860e54be3dbb6587611a9d61f6d28b4c825697
Change-Id: I598de6f83a86d528174d3d188596314572f5d70d
1 file changed