Replace usage of unittest module with manila.test

test modules
manila.tests.api.v1.test_share_networks
manila.tests.network.neutron.test_neutron_api
manila.tests.network.neutron.test_neutron_plugin

inherit unittest.TestCase, but all test classes
should inherit manila.test.TestCase

Also moved all predefines from __init__ to setUp

Change-Id: I07de752e6ca8cd206daeb966a75113239c6d411c
Merge "Replace usage of unittest module with manila.test"