Override stub path before PreEarlyInitDBus

Otherwise install attributes are not loaded on the linux Chrome OS
build.

TEST=manual

Bug: 848615, 729596
Change-Id: I445b2b337b707822459c076058610f49f02767ab
Reviewed-on: https://chromium-review.googlesource.com/c/1264643
Commit-Queue: Roman Sorokin <rsorokin@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Xi Han <hanxi@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#599138}(cherry picked from commit b80ea1c80ef7c8ec439c14def8120498fc35eda8)
Reviewed-on: https://chromium-review.googlesource.com/c/1294207
Cr-Commit-Position: refs/branch-heads/3578@{#225}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}
2 files changed