mwan3: fix race condition in route loading

Signed-off-by: Aaron Goodman <aaronjg@stanford.edu>

net/mwan3/files/usr/sbin/mwan3rtmon

@@ -158,6 +158,7 @@ main()
 	sh -c "echo \$\$; exec $IP monitor route" | {
 		read -r monitor_pid
 		trap_with_arg func_trap "$monitor_pid" SIGINT SIGTERM SIGKILL
+		KILL -SIGSTOP $$
 		while IFS='' read -r line; do
 			[ -z "${line##*table*}" ] && continue
 			LOG debug "handling route update $family '$line'"
@@ -165,11 +166,10 @@ main()
 		done
 	} &
 	child=$!
-	kill -SIGSTOP $child
 	trap_with_arg func_trap "$child" SIGINT SIGTERM SIGKILL
 	mwan3_set_connected_${family}
 	mwan3_add_all_routes ${family}
 	kill -SIGCONT $child
-	wait $!
+	wait $child
 }
 main "$@"