nfd: add option to set CS size

Don't append NFD logs b/w runs
Re-factor NFD start from ndn_host.py to bin/minindn

refs: #4469, #4508

Change-Id: I43f594a3353bb92101a0281a4561999cd8406707
diff --git a/ndn/ndn_host.py b/ndn/ndn_host.py
index 7c727ab..7596f5f 100644
--- a/ndn/ndn_host.py
+++ b/ndn/ndn_host.py
@@ -100,8 +100,7 @@
         self.cmd("mkdir -p %s" % self.homeFolder)
         self.cmd("cd %s" % self.homeFolder)
 
-        self.nfd = Nfd(self)
-        self.nfd.start()
+        self.nfd = None
 
         self.peerList = {}
 
@@ -116,7 +115,8 @@
 
     def terminate(self):
         "Stop node."
-        self.nfd.stop()
+        if self.nfd is not None:
+            self.nfd.stop()
         Host.terminate(self)
 
 class CpuLimitedNdnHost(CPULimitedHost, NdnHostCommon):
@@ -134,8 +134,7 @@
         self.cmd("mkdir -p %s" % self.homeFolder)
         self.cmd("cd %s" % self.homeFolder)
 
-        self.nfd = Nfd(self)
-        self.nfd.start()
+        self.nfd = None
 
         self.peerList = {}
 
@@ -150,8 +149,9 @@
 
     def terminate(self):
         "Stop node."
-        self.nfd.stop()
-        Host.terminate(self)
+        if self.nfd is not None:
+            self.nfd.stop()
+        CPULimitedHost.terminate(self)
 
 class RemoteNdnHost(RemoteMixin, NdnHost):
     "A node on a remote server"