mgmt+tools: rename 'datas' to 'data'

Plural form of 'data' is 'data'.

refs #3955

Change-Id: I62f5ebe53b8e36d565e5a243288eb12ae9a08014
diff --git a/tools/nfdc/face-module.cpp b/tools/nfdc/face-module.cpp
index 2ec3719..857956e 100644
--- a/tools/nfdc/face-module.cpp
+++ b/tools/nfdc/face-module.cpp
@@ -333,12 +333,12 @@
   os << "<packetCounters>";
   os << "<incomingPackets>"
      << "<nInterests>" << item.getNInInterests() << "</nInterests>"
-     << "<nDatas>" << item.getNInDatas() << "</nDatas>"
+     << "<nData>" << item.getNInData() << "</nData>"
      << "<nNacks>" << item.getNInNacks() << "</nNacks>"
      << "</incomingPackets>";
   os << "<outgoingPackets>"
      << "<nInterests>" << item.getNOutInterests() << "</nInterests>"
-     << "<nDatas>" << item.getNOutDatas() << "</nDatas>"
+     << "<nData>" << item.getNOutData() << "</nData>"
      << "<nNacks>" << item.getNOutNacks() << "</nNacks>"
      << "</outgoingPackets>";
   os << "</packetCounters>";
@@ -378,12 +378,12 @@
   os << ia("counters")
      << "{in={"
      << item.getNInInterests() << "i "
-     << item.getNInDatas() << "d "
+     << item.getNInData() << "d "
      << item.getNInNacks() << "n "
      << item.getNInBytes() << "B} "
      << "out={"
      << item.getNOutInterests() << "i "
-     << item.getNOutDatas() << "d "
+     << item.getNOutData() << "d "
      << item.getNOutNacks() << "n "
      << item.getNOutBytes() << "B}}";