This reverts commit 037f9b80.

Reason for revert: The structural change to manifest breaks the recipe
tester:
https://cs.chromium.org/chromium/infra/recipes/recipes/recipe_roll_tryjob.py?q=recipe_roll_tryjob.py&sq=package:chromium&dr&l=149
https://crbug.com/776299

Original change's description:
> bot_update recipe: Upload source manifest
> 
> Bug: 772529
> Change-Id: I3f833740ddfbc71be42b140c99dcd4bbfeed54fe
> Reviewed-on: https://chromium-review.googlesource.com/706071
> Commit-Queue: Ryan Tseng <hinoka@chromium.org>
> Reviewed-by: Robbie Iannucci <iannucci@chromium.org>

TBR=iannucci@chromium.org,hinoka@chromium.org,agable@chromium.org

Change-Id: Iba9653d73b7f117ca2f94619ae5da900cd0c8c98
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 772529,776299
Reviewed-on: https://chromium-review.googlesource.com/728059Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>