style: made container APIs more consistent.

Change-Id: Ib4feedfc4c9fb497dfcd67e7e6a33ee03db58d7f
refs: #4337
diff --git a/src/lsa.cpp b/src/lsa.cpp
index 440c2ba..ec27a35 100644
--- a/src/lsa.cpp
+++ b/src/lsa.cpp
@@ -68,7 +68,7 @@
 {
   std::ostringstream os;
   os << m_origRouter << "|" << NameLsa::TYPE_STRING << "|" << m_lsSeqNo << "|"
-     << ndn::time::toIsoString(m_expirationTimePoint) << "|" << m_npl.getSize();
+     << ndn::time::toIsoString(m_expirationTimePoint) << "|" << m_npl.size();
   for (const auto& name : m_npl.getNames()) {
     os << "|" << name;
   }
@@ -269,7 +269,7 @@
 {
   std::ostringstream os;
   os << m_origRouter << "|" << AdjLsa::TYPE_STRING << "|" << m_lsSeqNo << "|"
-     << ndn::time::toIsoString(m_expirationTimePoint) << "|" << m_adl.getSize();
+     << ndn::time::toIsoString(m_expirationTimePoint) << "|" << m_adl.size();
   for (const auto& adjacent : m_adl.getAdjList()) {
     os << "|" << adjacent.getName() << "|" << adjacent.getFaceUri()
        << "|" << adjacent.getLinkCost();