Neutron: Set experimental option to use linuxbridge agent

Recently the experimental mechanism has been added to Neutron and now
it requires the [experimental] linuxbridge option when the linuxbridge
mechanism driver is used.

Depends-on: https://review.opendev.org/c/openstack/neutron/+/845181
Change-Id: Ice82a391cda9eb0193f23e6794be7ab3df12c40b

Author: kajinamit

lib/neutron

@@ -229,6 +229,10 @@ function configure_neutron_new {
         else
             mech_drivers+=",linuxbridge"
         fi
+        if [[ "$mech_drivers" == *"linuxbridge"* ]]; then
+            iniset $NEUTRON_CONF experimental linuxbridge True
+        fi
+
         iniset $NEUTRON_CORE_PLUGIN_CONF ml2 mechanism_drivers $mech_drivers
         iniset $NEUTRON_CORE_PLUGIN_CONF ml2 overlay_ip_version $TUNNEL_IP_VERSION
 

lib/neutron_plugins/ml2

@@ -125,6 +125,9 @@ function neutron_plugin_configure_service {
     fi
 
     populate_ml2_config /$Q_PLUGIN_CONF_FILE ml2 mechanism_drivers=$Q_ML2_PLUGIN_MECHANISM_DRIVERS
+    if [[ "$Q_ML2_PLUGIN_MECHANISM_DRIVERS" == *"linuxbridge"* ]]; then
+        iniset $NEUTRON_CONF experimental linuxbridge True
+    fi
     populate_ml2_config /$Q_PLUGIN_CONF_FILE ml2 overlay_ip_version=$TUNNEL_IP_VERSION
 
     if [[ -n "$Q_ML2_PLUGIN_TYPE_DRIVERS" ]]; then