CLOUDSTACK-4473: allow_egress referenced before assignment

When deploying with networkids allow_egress gets no default value. This
is a regression caused by fix for CLOUDSTACK-4418

Signed-off-by: Prasanna Santhanam <tsp@apache.org>
(cherry picked from commit 239ba9447109412cf48cfefc547d6b5fef83a4a9)
Appropriately skip the test_nic setup when in a basic zone