openvswitch: Add ovs_wrapper for handling TERM

Partial-Bug: #2048130
Change-Id: I81eba2644eda6edd38c541f798bead04c2fa6578

docker/openvswitch/openvswitch-base/Dockerfile.j2

@@ -33,10 +33,12 @@ LABEL maintainer="{{ maintainer }}" name="{{ image_name }}" build-date="{{ build
 {% endblock %}
 
 COPY extend_start.sh /usr/local/bin/kolla_extend_start
+COPY ovs_wrapper.sh /usr/local/bin/ovs_wrapper
 
 # NOTE(hrw): Upstream moved tcpdump to /usr/bin/ in 4.99 version (used in Debian)
 RUN if [ -e /usr/sbin/tcpdump ]; then mv /usr/sbin/tcpdump /usr/bin/tcpdump; fi \
     && touch /usr/local/bin/kolla_openvswitch_extend_start \
-    && chmod 644 /usr/local/bin/kolla_extend_start /usr/local/bin/kolla_openvswitch_extend_start
+    && chmod 644 /usr/local/bin/kolla_extend_start /usr/local/bin/kolla_openvswitch_extend_start \
+    && chmod 755 /usr/local/bin/ovs_wrapper
 
 {% block openvswitch_base_footer %}{% endblock %}

docker/openvswitch/openvswitch-base/ovs_wrapper.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+catch_term() {
+    ovs-appctl -T1 -t /run/openvswitch/$1.$child.ctl exit
+    exit 0
+}
+
+catch_quit() {
+    ovs-appctl -T1 -t /run/openvswitch/$1.$child.ctl exit
+    exit 0
+}
+
+trap catch_term SIGTERM
+trap catch_quit SIGQUIT
+
+"$@" &
+
+child=$!
+wait "$child"