Do not consider subnets of shared public nets

Test test_external_network_visibility in
tempest.api.network.test_network fails when running
tempest against a deployment with public networks which
are shared among non-admin tenants.

This patch skips the public networks whose shared
property is set to true, as their subnets will be visible to
non-admin tenants.

Change-Id: Ieafb8e4094e603e259d68c4f485194a602dfc0cf
Closes-Bug: #1425962
1 file changed