Fix assumed default NFD socket path and add argument for socket path

Note that by default this commit will not work with NFD versions
earlier than 4c95771. In cases where this is required, an optional
argument is added to the Nfd class to change from the default.

Refs #5309

Change-Id: I70a43902dfbaf9a15c074fbac39b15d3db754f1d
diff --git a/minindn/apps/nfd.py b/minindn/apps/nfd.py
index 4b410b9..084dcf4 100644
--- a/minindn/apps/nfd.py
+++ b/minindn/apps/nfd.py
@@ -28,14 +28,15 @@
 class Nfd(Application):
 
     def __init__(self, node, logLevel='NONE', csSize=65536,
-                 csPolicy='lru', csUnsolicitedPolicy='drop-all'):
+                 csPolicy='lru', csUnsolicitedPolicy='drop-all',
+                 defaultSocketLocation='/run/nfd'):
         Application.__init__(self, node)
 
         self.logLevel = node.params['params'].get('nfd-log-level', logLevel)
 
         self.confFile = '{}/nfd.conf'.format(self.homeDir)
         self.logFile = 'nfd.log'
-        self.sockFile = '/run/{}.sock'.format(node.name)
+        self.sockFile = '{}/{}.sock'.format(defaultSocketLocation, node.name)
         self.ndnFolder = '{}/.ndn'.format(self.homeDir)
         self.clientConf = '{}/client.conf'.format(self.ndnFolder)