Revert "Enable port_security in gate to fix the neutron broken"

This reverts commit 94a882babe.

Upstream has fix this issue by Ice89ad9dd486ad5fcac534ef5f7d8aae3b6b0f97

Change-Id: Ib17f93e4030c6f7da4e32ee84fcc5f7139e57895
Closes-Bug: #1694420

tests/templates/globals-default.j2

@@ -19,13 +19,3 @@ enable_horizon: "yes"
 enable_heat: "no"
 openstack_logging_debug: "True"
 openstack_service_workers: "1"
-
-# enable port security in gate until this bug is fixed
-# https://bugs.launchpad.net/neutron/+bug/1694420
-extension_drivers:
-  - name: "qos"
-    enabled: "{{ '{{' }} enable_neutron_qos | bool {{ '}}' }}"
-  - name: "port_security"
-    enabled: true
-  - name: "dns"
-    enabled: "{{ '{{' }} enable_designate | bool {{ '}}' }}"