Also export zero-scores to Prolog

Zero scores can provide information, so also export them to Prolog rules.
(I.e. it might be interesting if the default score has been changed or
if you want to check if all users have provided a score.)

Bug: Issue 2741
Change-Id: Ie5b7ec67214e3a98ad3fa07b9bd3d45bc8cfdb89

gerrit-server/src/main/java/gerrit/PRED__load_commit_labels_1.java

@@ -43,10 +43,6 @@ class PRED__load_commit_labels_1 extends Predicate.P1 {
           StoredValues.CHANGE_CONTROL.get(engine).getLabelTypes();
 
       for (PatchSetApproval a : cd.currentApprovals()) {
-        if (a.getValue() == 0) {
-          continue;
-        }
-
         LabelType t = types.byLabel(a.getLabelId());
         if (t == null) {
           continue;