Exit test-network with status of chutney verify

Preserve previous semantics of src/test/test-network.sh by exiting with
the exit status of chutney verify, even though the latest version ends
with chutney stop.

src/test/test-network.sh

@@ -45,6 +45,8 @@ n=$BOOTSTRAP_TIME; while [ $n -gt 0 ]; do
     sleep 1; n=$(expr $n - 1); echo -n .
 done; echo ""
 ./chutney verify $CHUTNEY_NETWORK
+VERIFY_EXIT_STATUS=$?
 # work around a bug/feature in make -j2 (or more)
 # where make hangs if any child processes are still alive
 ./chutney stop $CHUTNEY_NETWORK
+exit $VERIFY_EXIT_STATUS