Right now there're 3 types of networks that are created in devstack:
* private
* public
* shared
This affects amount of resources that Vitrage is expecting to see
during one of tests. In order to ensure that we're accounting for each
type of networks that are present in deployment and that expected number
of resources is evaluated properly, we add extra logic of fetching
assumed networks and incrementing the counter.
Change-Id: Ib30db71a97bd40c3a73082c348c9eaff3adc43db