Make sure dist is created for the HEAD before uploading.

script/lib/util.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 
 import atexit
+import contextlib
 import errno
 import shutil
 import subprocess
@@ -18,6 +19,16 @@ def tempdir(prefix=''):
   return directory
 
 
+@contextlib.contextmanager
+def scoped_cwd(path):
+  cwd = os.getcwd()
+  os.chdir(path)
+  try:
+    yield
+  finally:
+    os.chdir(cwd)
+
+
 def download(text, url, path):
   with open(path, 'w') as local_file:
     web_file = urllib2.urlopen(url)