mod_spamassassin: Don't close file descriptor twice.

A soft assertion was triggered due to PIPE_CLOSE(output) closing an
already closed file descriptor. Use the CLOSE macro instead of close
to ensure the file descriptor is set to -1 after close, prior to the
PIPE_CLOSE call.

LBBS-100 #close

Author: InterLinked1

modules/mod_spamassassin.c

@@ -229,7 +229,7 @@ static int spam_filter_cb(struct smtp_filter_data *f)
 		headers_written++;
 	}
 
-	close(output[0]); /* Close read end to force child process to exit */
+	CLOSE(output[0]); /* Close read end to force child process to exit */
 	waitpid(pid, NULL, 0); /* Reap the child before exiting */
 	smtp_node(f->smtp)->childpid = 0;