Install upper_bound in ReadView:

*  And use it in doLedgerData.

src/ripple/ledger/impl/OpenView.cpp

@@ -178,6 +178,13 @@ OpenView::slesEnd() const ->
     return items_.slesEnd(*base_);
 }
 
+auto
+OpenView::slesUpperBound(uint256 const& key) const ->
+    std::unique_ptr<sles_type::iter_base>
+{
+    return items_.slesUpperBound(*base_, key);
+}
+
 auto
 OpenView::txsBegin() const ->
     std::unique_ptr<txs_type::iter_base>