Be more careful about when to close pull requests

* jeepyb/cmd/close_pull_requests.py: Only try to close pull requests
if actually configured to use GitHub. Also log verbose errors when
it fails to find the project there.

* jeepyb/projects.py: Add a convenience has_github function to
encode the somewhat twisty per-project override/default fallback
determination for the has-github global bool and local flag.

Change-Id: I0bbfabd2f110269cb8331383173f0dd588500778
2 files changed