Fix overriding of labels in child projects

The boolean logic here was wrong.  Permit overrides only
if the parent allows an override.

Change-Id: Ib2cce9d7eea6ca4c6036d3dce419bc338707442d

gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectState.java

@@ -349,7 +349,7 @@ public class ProjectState {
       for (LabelType type : s.getConfig().getLabelSections().values()) {
         String lower = type.getName().toLowerCase();
         LabelType old = types.get(lower);
-        if (old == null || !old.canOverride()) {
+        if (old == null || old.canOverride()) {
           types.put(lower, type);
         }
       }