CrOS FileApp remove unneeded test/OWNERS

Bug: 813477
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I96d3d4d4e6743ca584efff7b9e9b4712d4d198de
Reviewed-on: https://chromium-review.googlesource.com/1002212Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549094}

ui/file_manager/file_manager/test/OWNERS

-joelhockey@chromium.org
-sashab@chromium.org