smb_provider_client: Use BindOnce not Bind.

BUG=chromium:757625

Change-Id: I8d7b43df67660edb271345b75edbdfb744f498f2
Reviewed-on: https://chromium-review.googlesource.com/840882
Reviewed-by: Lutz Justen <ljusten@chromium.org>
Commit-Queue: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#528120}
1 file changed