change behavior: when user specify a language and there are no accepted submission, program will return the most recent non accepted submission in this language

Author: Jiati Le

lib/commands/submission.js

@@ -89,7 +89,7 @@ function exportSubmission(argv, problem, cb) {
     });
 
     // if no accepted, use the latest non-accepted one
-    submission = submission || submissions[0];
+    submission = submission || submissionInTargetType[0];
 
     var filename = sprintf('%s/%d.%s.%s.%s%s',
         argv.outdir,