"NeutronOvsdbIdl" should be a singleton class; only one instance
should be shared everywhere is called. Currently the connection
and the "OvsIdlMonitor" instances are global; those instances are
used to declare the "NeutronOvsdbIdl" instance.
As commented in the related bug, this singleton will ensure that
the OvsIdl indexes are created just once.
Change-Id: I639cf673a983b7b1be810495d8a8c2d89919a9b6
Related-Bug: #1881424
Rodolfo Alonso Hernandez
178227c8b6