Pulp

After a discussion related to an RFC I posted to pulp-dev, we've decided to stop using the LGTM tag and start using the github review system to approve PRs. While this change has been accepted and is now the expected workflow, we should update the docs to reflect this change, and take advantage of github's protected branch feature's support for this workflow.

This section should be adapted to no longer reference the LGTM tag:
http://docs.pulpproject.org/en/2.9/dev-guide/contributing/merging.html#merging-your-changes

This script should be updated to include review status in branch protection results:
https://github.com/pulp/devel/blob/master/scripts/protect-branches.py

The script's protect_branch function may also have to be updated to yield branches that have protection enabled, but not the correct branch protection settings (e.g. the branch is protected but still allows PR merges without review.

For reference: https://developer.github.com/v3/repos/branches/#update-branch-protection