cq_deps: Handle parent commits without CL

Handle parent commits that bypassed Gerrit and don't have CL numbers.

Change-Id: Ic362f55a14a8e3405551f9ba24e96b9f45d4005b
Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/23141
Commit-Queue: Rob Mohr <mohrr@google.com>
Reviewed-by: Oliver Newman <olivernewman@google.com>
4 files changed
tree: 59f4717e135629522129217fdaff9b82adb6542c
  1. infra/
  2. recipe_modules/
  3. recipes/
  4. .gitignore
  5. .style.yapf
  6. recipes.py