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
diff --git a/lib/neutron b/lib/neutron
index 1b78493..6e787f2 100644
--- a/lib/neutron
+++ b/lib/neutron
@@ -229,6 +229,10 @@
         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