unix/console.c: add a missing postmsg().

When abandoning a connection due to a host key mismatch in batch mode,
we'd forget to restore the termios settings.

unix/console.c

@@ -138,6 +138,7 @@ int console_verify_ssh_host_key(
     fprintf(stderr, common_fmt, keytype, fingerprints[fptype_default]);
     if (console_batch_mode) {
         fputs(console_abandoned_msg, stderr);
+        postmsg(&cf);
         return 0;
     }