face/rib/tools: avoid deprecate Block::fromBuffer overloads

refs #2553

Change-Id: I32ea424ab7547f59fea2fca70ad6f41cd90bab58
diff --git a/rib/rib-manager.cpp b/rib/rib-manager.cpp
index fa2c318..2b79a53 100644
--- a/rib/rib-manager.cpp
+++ b/rib/rib-manager.cpp
@@ -853,20 +853,20 @@
   size_t offset = 0;
   FaceIdSet activeFaces;
 
-  while (offset < buf->size())
-    {
-      if (!Block::fromBuffer(buf, offset, block))
-        {
-          std::cerr << "ERROR: cannot decode FaceStatus TLV" << std::endl;
-          break;
-        }
-
-      offset += block.size();
-
-      ndn::nfd::FaceStatus status(block);
-      activeFaces.insert(status.getFaceId());
+  while (offset < buf->size()) {
+    bool isOk = false;
+    std::tie(isOk, block) = Block::fromBuffer(buf, offset);
+    if (!isOk) {
+      std::cerr << "ERROR: cannot decode FaceStatus TLV" << std::endl;
+      break;
     }
 
+    offset += block.size();
+
+    ndn::nfd::FaceStatus status(block);
+    activeFaces.insert(status.getFaceId());
+  }
+
   // Look for face IDs that were registered but not active to find missed
   // face destroyed events
   for (FaceIdSet::iterator it = m_registeredFaces.begin(); it != m_registeredFaces.end(); ++it)