Don't run SQL rewrites when secondary index is enabled

If the secondary index is enabled on a server the index handles all
queries.  There is no reason to run the SQL rewrites or to leave
predicates in the predicate tree without being wrapped by the
IndexedChangeQuery predicate.

Change-Id: I18defed2a5a6003b9ae6ba227e29864b5c912e7b

gerrit-lucene/src/main/java/com/google/gerrit/lucene/QueryBuilder.java

@@ -121,8 +121,8 @@ public class QueryBuilder {
   private static Query sortKeyQuery(SortKeyPredicate p) {
     return NumericRangeQuery.newLongRange(
         p.getField().getName(),
-        p.getMinValue(),
-        p.getMaxValue(),
+        p.getMinValue() != Long.MIN_VALUE ? p.getMinValue() : null,
+        p.getMaxValue() != Long.MAX_VALUE ? p.getMaxValue() : null,
         true, true);
   }