Make _create_network() non-private

_create_network() is made public by this commit as
the tempest.scenario.manager interface is meant to be
consumed by tempest plugins.

Implements: blueprint tempest-scenario-manager-stable
Signed-off by: Soniya Vyas<svyas@redhat.com>

Change-Id: I3f6b8e274f9b57ae8d1389a188636660854971e3
3 files changed