Bug 1309 - Cannot publish LinkDiscovered event

* added back MD_SAL_TYPE for nodeConnectorId and nodeId for case when
nodeId and NodeConnectorId are not in openflow format (NodeId and
NodeConnector Ids are strings)
* added test that shows

Change-Id: I73438a14b0b32a9fd3b0bc311663ad29b7bd7dd1
Signed-off-by: Jan Hajnar <jhajnar@cisco.com>
Merge "Bug 1309 - Cannot publish LinkDiscovered event"