Tis commit enhances openstack_dashboard.test.helpers.TestCase
.add_panel_mocks() method to more flexible way.
Now the mock definitions are defined in the test settings and
setUp() in unit tests and selenium tests sets up mocks defined in
the test settings TEST_GLOBAL_MOCKS_ON_PANELS.
This is a preparation for drop of deprecated options (enable_firewall
and enable_vpn). They were marked as deprecated long ago, but they are
still kept just because we need a lot of changes in unit tests if dropped.
By this change, we no longer need to use settings just for testing.
enable_firewall/enable_vpn=False are dropped (default is True)
to confirm this change works well.
Related-Bug: #1687185
Change-Id: I0a5ebcf8d75e704420d3a5af46fde268a59aa9ec
b0a5f30248