SmbProviderClient: Change mount id to start at 0

Change SmbProviderClient to expect mount_id to start at 0.

CQ-DEPEND=CL:823086

Bug: chromium:757625
Change-Id: I55a13a0e15bf887176825e60c7297827fb45a017
Reviewed-on: https://chromium-review.googlesource.com/823270
Reviewed-by: Dan Erat <derat@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Allen Vicencio <allenvic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523837}
2 files changed