chdir to /opt instead of /root

- certain base images don't have /root, or even
  worse,  /root is a symlink pointing to a dir
  that does not exist.  For now, just use /opt
  and create /opt if needed.

workshop.pl

@@ -1940,9 +1940,13 @@ sub update_container_pkgs {
                 exit(get_exit_code('chroot_failed'));
             }
 
-            if (not chdir("/root")) {
+	    if (not -e "/opt") {
+                mkdir("/opt")
+            }
+
+            if (not chdir("/opt")) {
                 logger('info', "failed\n", 2);
-                logger('error', "Could not chdir to /root!\n");
+                logger('error', "Could not chdir to /opt!\n");
                 exit(get_exit_code('chdir_failed'));
             }