Remove limited patch set view of ChangeData

This required extra logic and state and complicated the semantics of a
ChangeData. It was only used by ChangeJson to limit results to a
single patch set. Instead of supporting arbitrary subsets of
revisions, just have ChangeJson do the limiting itself. The only
additional fetching this might require is for a single non-current
patch set, we might fetch all patch set rows for the change from the
db.

Change-Id: I7a35369d11da3b4b4d7f134766991f33c4a0b65c

gerrit-server/src/main/java/com/google/gerrit/server/ApprovalCopier.java

@@ -87,7 +87,7 @@ public class ApprovalCopier {
     try {
       ProjectState project =
           projectCache.checkedGet(cd.change().getDest().getParentKey());
-      ListMultimap<PatchSet.Id, PatchSetApproval> all = cd.allApprovalsMap();
+      ListMultimap<PatchSet.Id, PatchSetApproval> all = cd.approvalsMap();
 
       Table<String, Account.Id, PatchSetApproval> byUser =
           HashBasedTable.create();