Fix pci_request_id break the upgrade from icehouse to juno

commit a8a5d44c8aca218f00649232c2b8a46aee59b77e add pci_request_id
as one item for the request_network tuple. But the icehouse code
assume only three items in the tuple.

This patch filters pci_request_id out from the tuple.

Cherry-Pick from:
https://review.openstack.org/#/c/126144/6

Change-Id: I991e1c68324fe92fac647583f3ec8f6aec637913
Closes-Bug: #1377447
Merge "Fix pci_request_id break the upgrade from icehouse to juno" into proposed/juno