NLSR

1) NLSR fetches face dataset from NFD and creates routes to neighbors using corresponding face ids received in the face dataset
2) NLSR receives FACE_EVENT_CREATED with the neighbor faces (not sure why - because faces were created before NLSR was started).
3) NLSR does not check that we already have the face id set on the neighbor
4) NLSR proceeds to register routes again (harmless, but wasted)

Comment says about zero, but implementation is not there. There is an existing unit test to check this, but it is completely broken.

Solution:
NLSR should only proceed to register routes if known face id of neighbor is zero or the known face id is different from the received face id.