cansequence: do_receive(): fix error message if recvmsg() fails

In commit 9567230 ("cansequence: print out dropped packages by
socket counter"), the read() syscall was replaced by recvmsg(). Adjust
error message accordingly.

Fixes: 9567230 ("cansequence: print out dropped packages by socket counter")

cansequence.c

@@ -125,7 +125,7 @@ static void do_receive()
 
 		nbytes = recvmsg(s, &msg, 0);
 		if (nbytes < 0) {
-			perror("read()");
+			perror("recvmsg()");
 			exit(EXIT_FAILURE);
 		}