Accordind specs and docs, SRIOV_NIC.physical_device_mappings is not
limited to be a 1-1 mapping between physnets and NICs. However,
implementation requires this. This bugfix unlocks 1-M mappings, so one
physnet could be managed by many NICs.
* introduced unique_keys in neutron.utils.parse_mappings
* SRIOV_NIC.physical_device_mappings is parsed as dict with lists as
values with parse_mappings(..., unique_keys=False)
DocImpact
Change-Id: I07b8682fdfe8389a35893cc662b87c94a00bd4a5
Closes-Bug: #1558626
46ddaf4288