Since the NSS lib closes the socket the memory tracking system wrongly gets a

false positive on a leaked socket, so this introduces a way to tell the system
that the socket is indeed closed without explicitly closing it!

lib/nss.c

@@ -930,6 +930,7 @@ void Curl_nss_close(struct connectdata *conn, int sockindex)
 
     /* NSS closes the socket we previously handed to it, so we must mark it
        as closed to avoid double close */
+    fake_sclose(conn->sock[sockindex]);
     conn->sock[sockindex] = CURL_SOCKET_BAD;
     if(connssl->client_nickname != NULL) {
       free(connssl->client_nickname);