Files app: Remove debug logs

These logs were added as part of debugging flakiness, which has been
fixed, so removing the logs.

Test: No change in behaviour.
Bug: 899664
Change-Id: Ifb66c9beb6ab22bd1002dbda64dcbe461d5fb8e3
Reviewed-on: https://chromium-review.googlesource.com/c/1325269
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606285}