make registry v2 tests pass for GCS

Fixes #509.

storage/cloud.py

@@ -444,6 +444,8 @@ class GoogleCloudStorage(_CloudStorage):
     # TODO figure out how to handle cancel_on_error=False
     key.set_contents_from_stream(fp)
 
+    return key.size
+
 
 class RadosGWStorage(_CloudStorage):
   def __init__(self, hostname, is_secure, storage_path, access_key, secret_key, bucket_name):

util/registry/filelike.py

@@ -10,6 +10,9 @@ class BaseStreamFilelike(object):
     self._fileobj = fileobj
     self._cursor_position = 0
 
+  def close(self):
+    self._fileobj.close()
+
   def read(self, size=READ_UNTIL_END):
     buf = self._fileobj.read(size)
     self._cursor_position += len(buf)