chunks+peek: stop using deprecated {get,set}FinalBlockId

Change-Id: I64ae1c33a6f83af34b3db3d5f48cee3f3e7b7cb1
Refs: #4526
diff --git a/tools/chunks/catchunks/pipeline-interests-aimd.cpp b/tools/chunks/catchunks/pipeline-interests-aimd.cpp
index cdf502d..eac9dfd 100644
--- a/tools/chunks/catchunks/pipeline-interests-aimd.cpp
+++ b/tools/chunks/catchunks/pipeline-interests-aimd.cpp
@@ -215,8 +215,8 @@
   // Data name will not have extra components because MaxSuffixComponents is set to 1
   BOOST_ASSERT(data.getName().equals(interest.getName()));
 
-  if (!m_hasFinalBlockId && !data.getFinalBlockId().empty()) {
-    m_lastSegmentNo = data.getFinalBlockId().toSegment();
+  if (!m_hasFinalBlockId && data.getFinalBlock()) {
+    m_lastSegmentNo = data.getFinalBlock()->toSegment();
     m_hasFinalBlockId = true;
     cancelInFlightSegmentsGreaterThan(m_lastSegmentNo);
     if (m_hasFailure && m_lastSegmentNo >= m_failedSegNo) {