Prevent 500 errors on file move race condition.

 - Legacy-Id: 8480

Author: levkowetz

ietf/doc/expire.py

@@ -114,7 +114,13 @@ def move_file(f):
         dst = os.path.join(settings.INTERNET_DRAFT_ARCHIVE_DIR, f)
 
         if os.path.exists(src):
-            shutil.move(src, dst)
+            try:
+                shutil.move(src, dst)
+            except IOError as e:
+                if "No such file or directory" in str(e):
+                    pass
+                else:
+                    raise
 
     src_dir = Path(settings.INTERNET_DRAFT_PATH)
     for file in src_dir.glob("%s-%s.*" % (doc.name, rev)):