Support for exposing ports to host to allow external access to cord-tester ONOS.
Just set:
"expose_port" : true
in manifest file to enable host port bindings for external access to cord-tester ONOS containers.

Change-Id: I155b8669b39ad4de5075738ec49ba2af76a53f7c
diff --git a/src/test/utils/TestManifest.py b/src/test/utils/TestManifest.py
index 9d4825b..17de424 100644
--- a/src/test/utils/TestManifest.py
+++ b/src/test/utils/TestManifest.py
@@ -53,6 +53,7 @@
             self.voltha_loc = args.voltha_loc
             self.voltha_intf = args.voltha_intf
             self.voltha_enable = args.voltha_enable
+            self.expose_port = args.expose_port
         else:
             with open(self.manifest, 'r') as fd:
                 data = json.load(fd)
@@ -85,3 +86,4 @@
             if self.voltha_loc:
                 voltha_enable = True
             self.voltha_enable = data.get('voltha_enable', voltha_enable)
+            self.expose_port = data.get('expose_port', False)