Bug 872756 - pre: Bump Bagheera version to 0.11.
Bug 872756 - Part 0: Consume responses so that we release connections.
Bug 872756 - Part 1: Support multiple obsolete documents IDs in BagheeraClient.
Bug 872756 - Part 2: Record all potentially uploaded IDs for future deletion.
Bug 872756 - Part 3: Build out ObsoleteDocumentTracker API to not expose JSON.
Bug 872756 - Review comment: Factor out TEST_URL.
Bug 872756 - Follow-up: Improve logging of obsoleted IDs.
Bug 872756 - Follow-up: Bound the number of obsolete IDs stored.
Bug 872756 - Review comment: Update limits.