ovs-sandbox: add '--vswitchd-unforced-dummy' option.

The ovs-sandbox runs in the "dummy mode" by default.
In this mode of testing, no packets travel across
physical or virtual networks. But sometimes, we may
create veth network devices and add them to ovs bridge
for developing and testing. It's necessary to add an option.

Signed-off-by: nickcooper-zhangtonghao <nic@opencloud.tech>
Signed-off-by: Ben Pfaff <blp@ovn.org>

tutorial/ovs-sandbox

@@ -69,6 +69,7 @@ built=false
 ovn=false
 ovnsb_schema=
 ovnnb_schema=
+dummy=override
 
 for option; do
     # This option-parsing mechanism borrowed from a Autoconf-generated
@@ -112,6 +113,7 @@ These options force ovs-sandbox to use an installed Open vSwitch:
   --gdb-ovn-northd     run ovn-northd under gdb
   --gdb-ovn-controller run ovn-controller under gdb
   --gdb-ovn-controller-vtep run ovn-controller-vtep under gdb
+  --dummy=ARG          pass --enable-dummy=ARG to vswitchd (default: override)
   -R, --gdb-run        automatically start running the daemon in gdb
                        for any daemon set to run under gdb
   -S, --schema=FILE    use FILE as vswitch.ovsschema
@@ -135,6 +137,12 @@ EOF
             srcdir=$optarg
             built=false
             ;;
+        --dummy)
+            prev=dummy
+            ;;
+        --dummy=*)
+            dummy=$optarg
+            ;;
         -s|--sr*)
             prev=srcdir
             built=false
@@ -361,7 +369,7 @@ run ovs-vsctl --no-wait -- init
 
 # Start ovs-vswitchd.
 rungdb $gdb_vswitchd $gdb_vswitchd_ex ovs-vswitchd --detach --no-chdir --pidfile -vconsole:off --log-file \
-    --enable-dummy=override -vvconn -vnetdev_dummy
+    --enable-dummy=$dummy -vvconn -vnetdev_dummy
 
 if $ovn; then
     ovs-vsctl set open . external-ids:system-id=56b18105-5706-46ef-80c4-ff20979ab068