Implement MoveEntry on SmbProviderClient

This change implements MoveEntry on SmbProviderClient
and FakeSmbProviderClient.

BUG=chromium:757625
TEST=compiles

Change-Id: Icf38fa220dbb993a86f12e8c5464b93b18f06c3d
Reviewed-on: https://chromium-review.googlesource.com/923081


Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537924}