Some edges have old ID numbers, break GEXF export

[deemeetree]

http://www.knownodes.com/connection/71c52f1c-1c5a-458f-862e-e87e4ae00f6e

As you can see this connection is a bit strange – has two IDs that are in the old database structure and also that connection is retrieved when we're searching for all connections to resource /resource/a6077dc1-d440-40b2-92c1-34e9cb4e099f

Let me know what you think!