Don't process files in subdirectories

ocr

@@ -289,9 +289,8 @@ def collect_jobs(input_dir, output_dir):
     jobs = []
     for file in os.listdir(input_dir):
         if os.path.isdir(os.path.join(input_dir, file)):
-            jobs += collect_jobs(os.path.join(input_dir, file),
-                                 os.path.join(output_dir, file))
-        elif file.lower().endswith('.pdf'):
+            continue
+        if file.lower().endswith('.pdf'):
             job = OCRPipelineJob(os.path.join(input_dir, file),
                                  os.path.join(output_dir, file))
             jobs.append(job)