dump: capture in promisc mode by default, with an option to disable it

Change-Id: I75d9580616f0af588291897b27fe376921fef11f
diff --git a/tools/dump/ndndump.cpp b/tools/dump/ndndump.cpp
index 4c6d814..4c43826 100644
--- a/tools/dump/ndndump.cpp
+++ b/tools/dump/ndndump.cpp
@@ -82,7 +82,7 @@
 
   std::string action;
   if (!interface.empty()) {
-    m_pcap = pcap_open_live(interface.data(), 65535, 0, 1000, errbuf);
+    m_pcap = pcap_open_live(interface.data(), 65535, wantPromisc, 1000, errbuf);
     if (m_pcap == nullptr) {
       BOOST_THROW_EXCEPTION(Error("Cannot open interface " + interface + ": " + errbuf));
     }
@@ -117,7 +117,7 @@
   }
 
   if (!pcapFilter.empty()) {
-    if (isVerbose) {
+    if (wantVerbose) {
       std::cerr << "ndndump: using pcap filter: " << pcapFilter << std::endl;
     }