Fix zip path in packed API levels generation

Summary:
As title.

Fixes facebook#783.

Reviewed By: thezhangwei

Differential Revision: D45530098

fbshipit-source-id: 2701f042c52c280baba3cccd6db89f04467aea4b

gen_packed_apilevels.py

@@ -9,6 +9,7 @@
 import io
 import logging
 import os
+import shutil
 import zipfile
 from collections import namedtuple
 
@@ -57,7 +58,9 @@ def compress_zip(inputs):
         for input in inputs:
             logging.info("Adding %s", input)
             with open(input, "rb") as f:
-                zf.writestr(os.path.basename(input), f)
+                # Files are multi-MB, try to do it smartly.
+                with zf.open(os.path.basename(input), mode="w") as f2:
+                    shutil.copyfileobj(f, f2)
     buf.seek(0)
     return buf
 
@@ -144,7 +147,7 @@ def _all():
 
 def _load(name):
     global _ZIP
-    return _ZIP.read(names)
+    return _ZIP.read(name)
 
 
 def _all():