buffet: Fix buffet_client's use of proxies

The previous code would never work, because the ObjectManager
discovers the Buffet Manager asynchronously to its construction.

BUG=brillo:361
TEST=buffet_client commands work again.

Change-Id: I2f3f5c4c638e52e1d766a7d7ef78441ed23b7dbe
Reviewed-on: https://chromium-review.googlesource.com/255575
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Commit-Queue: Christopher Wiley <wiley@chromium.org>
Tested-by: Christopher Wiley <wiley@chromium.org>
1 file changed
tree: d5fadccfba8c0ef802cc19103d7d59973be97ea7
  1. buffet/