Fail when downloading/verifying the debug script fails

In the past we would continue but crashing is probably the better option as this would either indicate connection errors between domserver & judgehost or even a problem on the judgehost itself.

Author: Michael Vasseur

judge/judgedaemon.main.php

@@ -900,8 +900,8 @@ function fetch_executable_internal(
                     $run_config['hash']
                 );
                 if (isset($error)) {
-                    // FIXME
-                    continue;
+                    $scriptId = $judgeTask['run_script_id'];
+                    error("Retrieving/storing debug script '$scriptId' failed.");
                 }
 
                 $debug_cmd = implode(' ', array_map('dj_escapeshellarg',