Scripts/get_all_links: Properly close files

`get_all_links.py` opens files for reading urls in those, but do not
closes those.  This commit makes the script to properly close the files.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>

Scripts/get_all_links.py

@@ -56,6 +56,7 @@ def main(path):
             for ref in refs:
                 if ref not in urls:
                     urls.append(ref)
+        fd.close()
 
     #print(len(urls))