mgmt: report face MTU in faces/list and faces/query datasets

This commit also contains an overall cleanup of FaceManager
and extends the FaceDataset test case.

Change-Id: I8c8290b0dc04b25582e66a5c6dad3cca4dd226eb
Refs: #4763, #3325
diff --git a/tests/daemon/mgmt/cs-manager.t.cpp b/tests/daemon/mgmt/cs-manager.t.cpp
index 18e2cdc..1a485725 100644
--- a/tests/daemon/mgmt/cs-manager.t.cpp
+++ b/tests/daemon/mgmt/cs-manager.t.cpp
@@ -24,7 +24,9 @@
  */
 
 #include "mgmt/cs-manager.hpp"
+
 #include "nfd-manager-common-fixture.hpp"
+
 #include <ndn-cxx/mgmt/nfd/cs-info.hpp>
 
 namespace nfd {
@@ -199,7 +201,7 @@
 BOOST_AUTO_TEST_CASE(Info)
 {
   m_cs.setLimit(2681);
-  for (int i = 0; i < 310; ++i) {
+  for (uint64_t i = 0; i < 310; ++i) {
     m_cs.insert(*makeData(Name("/Q8H4oi4g").appendSequenceNumber(i)));
   }
   m_cs.enableAdmit(false);
@@ -207,7 +209,7 @@
   m_fwCnt.nCsHits.set(362);
   m_fwCnt.nCsMisses.set(1493);
 
-  receiveInterest(Interest("/localhost/nfd/cs/info"));
+  receiveInterest(Interest("/localhost/nfd/cs/info").setCanBePrefix(true));
   Block dataset = concatenateResponses();
   dataset.parse();
   BOOST_REQUIRE_EQUAL(dataset.elements_size(), 1);