Delete swarm_trigger recipe

Delete no-longer-used parts of swarming module and add "pragma: no
cover" where applicable.

BUG=skia:

Change-Id: I0f516d7be520a4d4b4efbfa97bd383a5f124e713
Reviewed-on: https://skia-review.googlesource.com/5790
Reviewed-by: Ravi Mistry <rmistry@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
35 files changed
tree: 98f21cfa756da8226f3d887c049bac6a2b2f668e
  1. recipe_modules/
  2. recipes.py
  3. recipes/