vchan-socket-proxy: Set closed FDs to -1

These FDs are closed, so set them to -1 so they are no longer valid.

Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Acked-by: Wei Liu <wl@xen.org>
Reviewed-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Release-acked-by: Paul Durrant <paul@xen.org>

tools/libvchan/vchan-socket-proxy.c

@@ -326,7 +326,9 @@ int data_loop(struct vchan_proxy_state *state)
                 while (outsiz)
                     socket_wr(state->output_fd);
                 close(state->output_fd);
+                state->output_fd = -1;
                 close(state->input_fd);
+                state->input_fd = -1;
                 discard_buffers(state->ctrl);
                 break;
             }