Correct capitalisation of two Luxi calls

Two Luxi calls have inconsistent an name/value mapping (in the Python
code):

- REQ_AUTOARCHIVE_JOBS versus AutoArchiveJobs (versus AutoarchiveJobs)
- REQ_QUEUE_SET_DRAIN_FLAG versus SetDrainFlag (no Queue)

While these are only a consistency issue, let's fix them so that the
Haskell code (which uses the auto-generated camel-case form) doesn't
need to handle them case specially, and looks more like the Python
code (hah, joke!).

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: René Nussbaumer <rn@google.com>