Fix negative unit test for sec group rules

Ensure the test fails because the security group
rule could not be created, and not because the security
group was deleted before creating the rule.

Closes-Bug: #1268561

Change-Id: Ib2ea8c4507862d7bb343ce5181cf018b3cdf4b73
Configure plugins by name

To configure core plugin or service plugins, instead of using class names,
simpler names can also be used, ex:

service_plugins = router, firewall, lbaas

For compatibility with previous versions, the class name of a plugin can be
specified instead of its entrypoint name, ex:

service_plugins = router, neutron.services.firewall.fwaas_plugin.FirewallPlugin, lbaas

DocImpact

Implements: blueprint config-plugin-by-name
Change-Id: Ia4aaa1d305b160a4d6dab9e227c744727a4c78c2
Merge "Fix negative unit test for sec group rules"
Merge "Configure plugins by name"