proxy: calling Close() on the Accept()ing fd won't cause it to return

This seems to be a difference between the AF_VSOCK and AF_INET
implementations. We work around it by exiting the proxy process
immediately, which will clean up resources anyway.

Signed-off-by: David Scott <dave.scott@docker.com>

alpine/packages/proxy/proxy.go

@@ -67,6 +67,8 @@ func handleStopSignals(p libproxy.Proxy) {
 	signal.Notify(s, os.Interrupt, syscall.SIGTERM, syscall.SIGSTOP)
 
 	for range s {
-		p.Close()
+		os.Exit(0)
+		// The vsock proxy cannot be shutdown the same way as the TCP one:
+		//p.Close()
 	}
 }