ChangeData: Remove unused cherryPickOf variable

Change-Id: I17dbab3b53c8d6de7d3d8f0d8e1115b0fc754ec0
diff --git a/java/com/google/gerrit/server/query/change/ChangeData.java b/java/com/google/gerrit/server/query/change/ChangeData.java
index 8879388..883f550 100644
--- a/java/com/google/gerrit/server/query/change/ChangeData.java
+++ b/java/com/google/gerrit/server/query/change/ChangeData.java
@@ -300,7 +300,6 @@
   private Integer unresolvedCommentCount;
   private Integer totalCommentCount;
   private LabelTypes labelTypes;
-  private Optional<PatchSet.Id> cherryPickOf;
 
   private ImmutableList<byte[]> refStates;
   private ImmutableList<byte[]> refStatePatterns;