cansequence: exit program with failure in case of poll timeout

The poll function returns 0 to indicate a call timed out.

Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>

cansequence.c

@@ -216,7 +216,7 @@ static void do_send()
 				}
 
 				err = poll(fds, 1, 1000);
-				if (err == -1 && errno != -EINTR) {
+				if (err == 0 || (err == -1 && errno != -EINTR)) {
 					perror("poll()");
 					exit(EXIT_FAILURE);
 				}