Print proper name for QuerySource tasks in show-queue command

Before this commit, the tasks name were printed like this:

com.google.gerrit.lucene.LuceneChangeIndex$QuerySource$1@77352d29

Now, the Lucene query is printed, example:

((status:new OR status:draft) owner:1000001)

Change-Id: I9a08a8eef08af5dba9b0948b9ae445a807fe8b87

1 files changed, 14 insertions, 6 deletions

diff --git a/gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneChangeIndex.java b/gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneChangeIndex.java
index c8099d2189..6af320f480 100644
--- a/gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneChangeIndex.java
+++ b/gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneChangeIndex.java
@@ -367,8 +367,7 @@ public class LuceneChangeIndex implements ChangeIndex {
     if (!Sets.intersection(statuses, CLOSED_STATUSES).isEmpty()) {
       indexes.add(closedIndex);
     }
-    return new QuerySource(indexes, queryBuilder.toQuery(p), opts,
-        getSort());
+    return new QuerySource(indexes, p, opts, getSort());
   }
 
   @Override
@@ -401,14 +400,18 @@ public class LuceneChangeIndex implements ChangeIndex {
 
   private class QuerySource implements ChangeDataSource {
     private final List<SubIndex> indexes;
+    private final Predicate<ChangeData> predicate;
     private final Query query;
     private final QueryOptions opts;
     private final Sort sort;
 
-    private QuerySource(List<SubIndex> indexes, Query query, QueryOptions opts,
-        Sort sort) {
+
+    private QuerySource(List<SubIndex> indexes, Predicate<ChangeData> predicate,
+        QueryOptions opts, Sort sort) throws QueryParseException {
       this.indexes = indexes;
-      this.query = checkNotNull(query, "null query from Lucene");
+      this.predicate = predicate;
+      this.query = checkNotNull(queryBuilder.toQuery(predicate),
+          "null query from Lucene");
       this.opts = opts;
       this.sort = sort;
     }
@@ -425,7 +428,7 @@ public class LuceneChangeIndex implements ChangeIndex {
 
     @Override
     public String toString() {
-      return query.toString();
+      return predicate.toString();
     }
 
     @Override
@@ -440,6 +443,11 @@ public class LuceneChangeIndex implements ChangeIndex {
             public List<Document> call() throws OrmException {
               return doRead();
             }
+
+            @Override
+            public String toString() {
+              return predicate.toString();
+            }
           }));
     }