Filter out external networks in NetworksSearchCriteriaTest
Filter out external networks in NetworksSearchCriteriaTest

Otherwise those networks that may even belong to another tenant still
show up in the results that we then compare iterated networks to.

Change-Id: I24b117401a1886dce0b78900b522ac9bace533bf
Closes-Bug: #1614964

igor-toga/local-snat,noironetworks/neutron,huntxu/neutron,huntxu/neutron,igor-toga/local-snat,cloudbase/neutron,mahak/neutron,openstack/neutron,cloudbase/neutron,sebrandon1/neutron,mahak/neutron,openstack/neutron,eayunstack/neutron,mahak/neutron,openstack/neutron,noironetworks/neutron,eayunstack/neutron,sebrandon1/neutron