NACK reason "No PIT Entry found"

[cmarxer]

NACK reason "No PIT Entry found" looks wrong and should be reviewed. Seen twice:

Layers/NFNLayer/test/test_BasicNFNLayer.py:242:

nack = Nack(name, reason="No PIT Entry found", interest=interest)

Layers/NFNLayer/test/test_BasicNFNLayer.py:267:

nack = Nack(name, reason="No PIT Entry found", interest=interest)

[blacksheeep]

I assume this should be: "No FIB entry found" but I have to double check that.