Fixes for Onos cord instance wrapper restart case.
Add a exception marker for logs with exceptions.

Change-Id: Ic68f15ba777768ab040c89985d7044cdf1867ef7
diff --git a/src/test/utils/CordContainer.py b/src/test/utils/CordContainer.py
index 5f1ea2c..d1db4ff 100644
--- a/src/test/utils/CordContainer.py
+++ b/src/test/utils/CordContainer.py
@@ -352,7 +352,7 @@
             self.start()
 
     def start(self, restart = False, network_cfg = None):
-        if network_cfg:
+        if network_cfg is not None:
             json_data = json.dumps(network_cfg, indent=4)
             with open('{}/network-cfg.json'.format(self.onos_config_dir), 'w') as f:
                 f.write(json_data)
diff --git a/src/test/utils/CordTestServer.py b/src/test/utils/CordTestServer.py
index 1359850..c302d8c 100644
--- a/src/test/utils/CordTestServer.py
+++ b/src/test/utils/CordTestServer.py
@@ -37,7 +37,7 @@
 
     def __restart_onos(self, node = None, config = None, timeout = 10):
         if self.onos_cord:
-            onos_config = '{}/network-cfg.json'.format(OnosCord.onos_config_dir)
+            onos_config = '{}/network-cfg.json'.format(self.onos_cord.onos_config_dir)
         else:
             onos_config = '{}/network-cfg.json'.format(Onos.host_config_dir)
         if config is None:
diff --git a/src/test/utils/OnosLog.py b/src/test/utils/OnosLog.py
index a5e0fa7..0a31b80 100644
--- a/src/test/utils/OnosLog.py
+++ b/src/test/utils/OnosLog.py
@@ -53,7 +53,9 @@
                         if t == 'Exception':
                             exception_map[t] = lines[i+1:i+1+10]
             output = '\n'.join(match_lines)
-            output += '\n'.join(exception_map['Exception'])
+            if len(exception_map['Exception']) > 0:
+                output += '\nException:\n'
+                output += '\n'.join(exception_map['Exception'])
 
         #update the last snapshot
         if cache_result is True: