'Teardown the link.
Removes endpoints from properties I{links} collection.
@return: self
@rtype: L{Link}'

def teardown(self):

    (pA, pB) = self.endpoints
    if (pA in pB.links):
        pB.links.remove(pA)
    if (pB in pA.links):
        pA.links.remove(pB)
    return self
